# Erich's Benchtop Gear Hobber Project



## ErichKeane (Aug 29, 2022)

Inspired by @vtcnc and others, I've decided to make my next project a benchtop gear hobber!  I opted to buy from Martin Models (see my thread here: https://www.hobby-machinist.com/threads/visited-martin-models-today.101648/  for my trip report), which seems like a nice revision of the standard kit with some nice looking options/changes.

Also, it comes with some plans that are seemingly not too bad quality wise.  There is some work to be done to track down some of the dimensions, but the first few parts seem like they aren't too confusing.  I plan to work 'bottom up' like I usually do, to try to 'use up' castings and bolt them together as soon as possible 

Castings seem like they are really high quality and generously sized:












And here they are (well, most of them...) arranged more or less how they will end up when assembled, useful for my visualization purposes


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## mattthemuppet2 (Aug 29, 2022)

this will be a fun build to follow!


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## vtcnc (Aug 30, 2022)

ErichKeane said:


> View attachment 418637
> View attachment 418638


I don't know how many I times I did this with my set of castings. Just sat there visualizing and then my wife catching me zoning out in my head thinking the project through. These photos made me chuckle.

Looking forward to your build. You aren't far behind me and I anticipate you will pull ahead soon. I won't be getting back to mine for a little bit yet.

Subscribed!


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## ErichKeane (Aug 31, 2022)

So I spent yesterday evening going over the plans as best I could, without some level of instruction or an assembly diagram, it is pretty confusing, and I think I found a few dimensions that are either confusing, or incorrect.  It also does an annoying job of mixing radius and diameter in a few places.  I got a feeling there are a few pieces missing from the drawings, so I think I'll have to engineer a couple as I go along.

One thing I'm particularly confused about is the dial mounts section of the feed screws, which doesn't really make sense/add up to me.  BUT thats a problem for a later-date, and I can engineer something when I get there.

One thing I DID notice, is it is designed with an NMTB20 tool-holder for both the work holder spindle and the hobber holder spindle.  I cannot for the life of me find a half-decent source of those, so I might find myself replacing those with something like MT2 along the way.

All that said, this looks like it'll be a fun kit to work on!

THAT SAID, I studied the base plate, and the 3 pieces that connect to it directly, and am pretty confident I know enough to get that done correct, AND understand what are the important dimensions/locations.

I started by filing casting marks off the base and hobber-spindle-housing  I wanted to start by flattening the base, but need to get a very heavy vice off the shaper, so I can do it over there first 

SO, I decided to first machine the hobber spindle housing, which has the hobber spindle (which holds a tool holder on one side, and has a drive pulley and gear on the other).

I started by facing the bottom flat, which is going to allow me to setup the important reference surfaces:




I ended up adding packing there a little later.


Next, I had to find the 'center line' best I could, which I did with a wiggler and by eye:




Next, I need 'zero' face on this side (the gear/drive pulley side) to base some other measurements off of.  the sticking out part of the cylinder will have the quadrant arms on it, so that boss needs to be turned to this face.  Also, this is the 'zero' for alignment with the "EL" bracket that holds the other part of the gear train.




Next, I squared up the sides, based on my 'center' point, so that the flanges are the same size on each side.  This will be useful as indexing surfaces in the future I believe.



The plans call for a key-stock alignment pin, so I cut a 1/8x1/16 slot down the center.  This should make sure this stays square to the other components on the base.




FINALLY, I flipped it up on its back side with a parallel against the indexing face I made earlier, and flattened the 'hob' side.  This needs to be flat because I'm going to use it to index in the 4 jaw chuck later on when I start cutting the bores.  ALSO of importance, the area around the bore has a bolt-pattern that I'll have to cut at one point or another, so this being flat will be handy then.



That was it for today!  I'm probably going to hold off on the bore until I get the bearings I need delivered, so my next step is probably doing the shaping on the base, then the milling necessary there (like drilling all mounting holes/etc), and then probably the 'EL' gear holder.


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## ErichKeane (Aug 31, 2022)

Decided to spend another 90 minutes working after dinner. I got the vise off my shaper table, and got the base strapped down. The plans say the three pads need to be parallel and flat, but not coplanar.

It also says not to machine the bottom of the feet. Since I'm doing the top of this in 2 operations (it needs time on the mill as well), I think I'm going to try to get these all coplanar so I can mill the feet coplanar as well, then use them when strapping it down to mill the mount holes and alignment holes.

I got about 1/4 of the way through the shaping work, using a shear tool I ground tonight. The finish is gorgeous and very flat, despite the appearance and a large step over.

After my first two passes:



The shear tool in action:



And finally, where I gave up at the end of the night:



The top left pad there is higher than the others by quite a bit, and the whole thing is high in the center, so it might require taking quite a bit of material to get coplanar.


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## AGCB97 (Sep 1, 2022)

So, what will you use for hobs? I still have some, gear and thread, mostly in good condition. For me they make good paper weights.
Aaron


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## ErichKeane (Sep 1, 2022)

AGCB97 said:


> So, what will you use for hobs? I still have some, gear and thread, mostly in good condition. For me they make good paper weights.
> Aaron


Its pretty flexible on hobs, I just have to turn a new hob-holder each time.  At the moment, I haven't gotten that far, but I'm intending to see what is available on ebay when the time comes.


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## ErichKeane (Sep 1, 2022)

More progress today! I had 3 machines running at a time for a while, so I went back and forth quite a bit.  But, I finished flattening the base on the shaper with the shear tool. There was a pretty serious crest in the casting, so I found myself cutting into the part number a bit. Not sure if I will grind that off before painting.




On the mill, I worked on the "EL", which is a part that holds part of the gear set. Most of the dimensions are not critical, just that the outside face needs to be flat and square to the base. Everything else can be taken up by a quadrant arm and washers in between the gears. I started by trying to flatten the main face:




This went bad, I got chatter like no one's business on that far end. I  opted instead to go a different path. By thinning out the riser, I could make the sides of that my reference surface (and, get it a little nicer looking).



Once I had the first face done, I was able to flip it over on a parallel and get the other side easily enough!




From there, I could squeeze those faces in the vise and have a basically fully supported for 90 percent of the way. I had to use a small shim to keep up the hanging side to stop chatter, but operation success!



At this point I could have used the big endmill to do the base, but I was afraid of the overhang. Instead I opted to do the rest of the operations on my fixture plate with a big endmill:



I drilled the end holes smaller, then used a 1/2" endmill to mill the slot:




For my last milling operation, I need to essentially spot face down the part. I opted to just machine it all the way down, swapping clamps as I went, but the last overhang ended up a little thin on one side thanks to some lift feom the endmill.

After that, just mounting holes! The distance from face to the bottom hole is the only really relevant dimension, so I laid it flat and used a height gauge to measure.

I used a hand drill to drill them, figuring I can upsize it if necessary/too inaccurate.




I wasn't confident I could do that in the mill (I need a horizontal mill I guess!), So this worked out fine enough.

Tomorrow if I get shop time, I plan on finishing the base by drilling all the mounting holes.


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## vtcnc (Sep 4, 2022)

Looking good!


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## pdentrem (Sep 4, 2022)

Been looking at this kit for a few years now.


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## ErichKeane (Sep 4, 2022)

pdentrem said:


> Been looking at this kit for a few years now.


The hobber looks pretty nice! The plans are 5/10, but the castings are beautiful. I'd suggest getting it now so you can follow along with my build  

If you can convince a few others, I could talk Gary into a group buy.


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## ErichKeane (Sep 6, 2022)

Alright, another interesting day, this time I tackled and finished the 'base'.  Usually I would do something like this first, but wasn't convinced right away I had all the necessary dimensions.  

First, despite what the plans say (which is not to!), I opted to flatten the feet. I figure it was counting on a single setup in the mill to do the whole top, and I did it in 2 operations.  I couldn't get it to sit flat enough on the mill without doing this, but when done, I was perfectly flat:




Next, I flipped it over and used a wiggler to find a straight-ish part of the casting flats to set my zeros:




SO the big important thing I figured out is what is the important dimensions.  FIRST, there is 3 pads.  The hole patterns inside each one are critical, but the dimensions between them are NOT critical, with 1 exception. The MOST critical part is that they are all 'square' to each-other, so it is important to do all the holes/etc in 1 setup.

The ONE important relationship is that the bottom left and top left pads share a left-side 'zero'.  Additionally, the dimensions on the top-left (the .750 from the RHS of the flat) ACTUALLY should be relative to the LHS of the flat.  THis is because the relationship between the 'EL' piece we made earlier and the hob-holder spindle are important.

I started by drilling/tapping the lower-left, and convinced myself I got it right enough to move on.  Then I started the upper left by cutting the groove for the keystock. Plans call for just a piece on each side for this one, but I chose instead to cut it all the way across, so I could use a single piece if I cared to.




Finally, I drilled/tapped the holes in it, and this pad was done!




The lower right went similarly, and centered the stuff on the pad rather than try to make it relative to the other two pads (which wasn't on the plans anyway!).

I drilled the holes (not tapped, the bolts come in from the bottom!), and cut the keyway slot in this one too.  Note that I COULDN'T go all the way across, because for some reason the key would go through the 3 bottom mounting holes.

I DID have a minor oopsie on this one as you can see to the left of the left key-stock slot. While raising the table to cut the final cut, I nipped into the top of the casting ~2 thou.  I'm hopeful no one here will tell on me once this gets painted 





SO, the base is done! I couldn't find my stash of 1/4-20 bolts to pop the two other parts onto this in the meantime, so thats all the pics I have today.

ADDITIONALLY, I started to try to setup for the hob-spindle-holder stuff since my bearings were on their way, but I couldn't get my 6 jaw off the lathe!  I suspect that is going to be my next big thing.  Mixed with the pass-around-box showing up today, I wasn't going to get anything else done


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## ErichKeane (Sep 7, 2022)

So, two steps back kinda day:/ I wanted to get one side of the features set up right on the gear hobber spindle holder. It took ages to get the first setup right in the 4 jaw, but I got it where I was somewhat happy with it.  Unfortunately I had a momentary lapse, and crashed into the face while cutting the outside diameter.

I just couldn't get it back in place either right, and attempts to recut just ended up making the part too thin. Finally, turns out my facing job is likely not square, so I would have to do that again too.

I decided to scrap the part, and I'll have to try it again. My thought is to try to use the mill and boring head for as much as I can next time, since the work holding is easier. Sadly, that is harder to get a square inside face on the bores, but they are less important than the diameters.

I figure I'll get through as many castings as I can before reordering to save myself multiple drives or an extra shipping box.

So next time I'll work on a different part.


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## vtcnc (Sep 9, 2022)

ErichKeane said:


> So, two steps back kinda day:/ I wanted to get one side of the features set up right on the gear hobber spindle holder. It took ages to get the first setup right in the 4 jaw, but I got it where I was somewhat happy with it.  Unfortunately I had a momentary lapse, and crashed into the face while cutting the outside diameter.
> 
> I just couldn't get it back in place either right, and attempts to recut just ended up making the part too thin. Finally, turns out my facing job is likely not square, so I would have to do that again too.
> 
> ...


I'm curious about the padding on your 4 jaw setup with this. One pair of jaws is inverted. I'm not exactly following what you intended with this setup.


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## ErichKeane (Sep 9, 2022)

vtcnc said:


> I'm curious about the padding on your 4 jaw setup with this. One pair of jaws is inverted. I'm not exactly following what you intended with this setup.


My problem was that I needed the step jaws as a flat surface to reference the flat face on the back. However, if I used all 4 step jaws, even with a bunch of packing, the jaws were interfering. So by swapping that one around, it didn't hit the side two (or vice versa).


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## ErichKeane (Sep 10, 2022)

SO I did some work with the first/lowest 'slide' on Thursday, and finally have time to type about it 

This is a casting that bolts to the base, and ends up being the fixed slide for the longitudinal motion. I don't have the ball-endmill to get this done, but started it anyway.

First I stood it straight up and cleaned up a 'small' edge.  Next, I faced the bottom:




About 40-50 thou off of it, and it was pretty well cleaned up.


Next, I flipped it over, and did the top, machining to final thickness.



Then I did the short sides this way.



Finally, I machined to width by standing it up. (no picture).

My last operation of the day was the two slots for keystock, and drilling and tapping the holes used to mount it to the base:




Next time I'm in the shop, I'll likely have my ball-endmill to cut the center relief, plus the dovetail cutter to get that all done right too.  I'll probably skip the 'nut mount' for a bit, until I have the nut part made and ready to match-machine.


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## ErichKeane (Sep 20, 2022)

I FINALLY got a chance to get back to the project after quite a while.  I decided to spend today doing some more work on the longitudinal cross slide.

First, I needed a relief with a ball endmill down the center:




This is just clearance for the lead screw.  Next, I needed to cut the dovetails on it.  They need to be coplaner/etc, but otherwise the dimensions don't really matter all that much (AND aren't well defined in the diagrams/in a way that can be measured well).  There is an adjustable brass gib that goes on 1 side and makes one side 'deeper' than the other by about 150 thou.  Otherwise, this went easy enough.






There is 1 more step on this piece (a place to mount the 'nut'), but I'm holding off until I can make the nut, and bore the spot to fit.


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## vtcnc (Sep 21, 2022)

I need to catch up to you!


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## ErichKeane (Sep 22, 2022)

Alright, slight detour today. The last thing I have to do to the bottom slide is cut room for the nut to mount. However, I decided to make the nuts first.

The plans suggest modifying a set of $40/each nuts from McMaster, which I DID, but probably would not have done again. I should have just bought the material and a tap. 

First, I indicated a piece of allthread in the 4 jaw:
	

		
			
		

		
	




Mounted the nut from McMaster:






Then turned it to shape. As you can see.




Most of the material from McMaster was wasted, and the thread wasn't centered very well in it anyway! If I were to do it again, I'd just buy raw stock and make it myself. Probably would have been more accurate, since I could turn the OD and do the thread in a single op.


Next step was to turn the top into a flange with room for #4 screws. One of the dimensions on the plans was wrong (it says the flange should be 1.084*.650, but elsewhere it has me make a .625 pocket!), So this was corrected.




And, all done! That's it for today


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## ErichKeane (Sep 22, 2022)

Alright, my wife took longer than I expected to get home, so I got a little more work done. I decided to finish the slide.

I stood it up in the vise, and prayed it would be stiff enough. I edge found, center drilled, then did a .375 stubby about to the right distance. The bottom of the hole chartered a bit, but clearance for a boring bar was done 




Next, some long cuts on power feed with the boring head. Ended up getting about the nicest slip fit I could hope for! The chatter near the bottom of the hole cleared up for the most part



Next, I cleared out room for the flange:



And drilled/tapped #4-40 for the mounting screws:



I don't have the screws I need yet, but here it is slipped into place:



This makes the bottom slide all done!


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## rwm (Sep 24, 2022)

That looks beautiful!


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## ErichKeane (Sep 26, 2022)

Got picture happy today, and also got a whole part done! The WRONG part, but a whole one.  I started by trying to work on the longitudinal slide, the other half of the dovetail I did above.

First, I faced 1 side:



Then, skimmed the back as thin as I could:



I flipped it to start the dovetail, but got 1 of the long dimension sides done too while I had a chance!




Then, I went to set the depth of the dovetail. I noticed that I couldn't clean up the whole casting. Additionally, I ALSO noticed that the casting number was FOUR, not THREE! Fortunately, both are identical in dimension and purpose, except for the features on top. However, in case someone looks at the casting number I couldnt clean up someday, I decided to finish this one as the feed slide.

I used the DRO to get the dovetail centered and to width, as the dimension was specified at the BOTTOM point of the dovetail! Oh ,well, depth and centered is most important, and the DRO got the width right.



Next I did the top face. This is where the two slides differ: this one uses a pin and 2 1/4-20 bolts to allow the gear to sit at an angle. Simple enough with the DRO.




The next thing I needed was the mount for the lead screw bracket. Two 1/4-20 holes centered on the dovetail is all that took.
	

		
			
		

		
	




Next, the gib tightening screws and alignment pin. The plans switch between #6 and #8-32 depending here, but I decided to just do #8 on the whole thing.
The plans also say to use a 1/8" pin hole, but I only have a 3/16" reamer: so that's what I'm going with 

Also, the holes were on .915" centers, which was strange, and didn't really leave the ends even, but I figured there might be a good reason for it, so I had a sheet of paper with all the measurements for exactly that reason



And that's it! Part is done:
	

		
			
		

		
	





Not the part I set out to make, but a part off the list anyway. Next I'll probably go do the part I intended, though I'll take fewer pics, since it is the same part more or less.


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## ErichKeane (Sep 27, 2022)

Heh, so turns out it was fortunate I got the wrong part   The 'correct' part ends up needing a T-slot of a bizarre set of dimensions that I can't really find a cutter that will cut.  It is only 3/8" wide, but has a 3/4" 'flange', only 1/8" thick.  

None of the woodruff cutters are a size that I think looks good, so I ordered a cheap T slot cutter on amazon that I'm hopeful I can turn into a good T-slot.  

SO, if I get time to work today, I'm likely going to work on a different part while I wait for my T slot cutter.  It would be nice to have one that will take me a few days, so I'm not waiting around too long, or delaying the other part while my notes from the other part are still readable


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## ErichKeane (Sep 27, 2022)

So as promised, I did a different part today! This is two dovetail slide parts as 1 casting! The piece I made last night goes on 1 side, and the other attaches up/down on an angle plate. This makes up the "up/down" and "feed" adjustment.

First, I hit it with a file to get this to work then with some copper wire packing material, got it so I could start machining it in the vise.



First I squared off the whole part, which I can use for index surfaces later.



Next, I tried to cut the dovetail. Unfortunately, right as I finished, I realized that SOMETHING moved. I strongly suspected the fit in the vise, so instead of fixing it, I opted to do the other block FIRST, so I would have a good clamping spot.


Also, I over cut the bottom(left here) thanks to a math issue (the plans are nuts with how they dimension this...), So I'll have to fix that too.

As mentioned, I flipped it over, did the outside dimensions, then cut this dovetail. This one was pretty easy going: 
	

		
			
		

		
	




Then I flipped it back over, and cut the bad dovetail again. I had to cut a good amount deeper, AND thanks to my transcription error, 40 thou "high", but this went well enough as well:






I also faced the top to get the dovetail heights right, but I suspect I'll have to take a few thou out of this somewhere at one point, since the plans seem like they will interfere. I'll likely get some surface grinder time during assembly 

Next, I cut the relief for the lead screw. However, I thought the depth was a mistake in the plans so I cut it too shallow. I did not notice until I tried to assemble stuff, but I'll be able to get it right easy enough best time I'm working on this.



I spent some time with the boring head for the nut:



Then machined the relief for it, plus the screw holes. So, this half of the part is done. I just need another bit of time doing the mount holes + gib screws on the other side.




So, reasonably successful day. I need another hour on this part, then I can call it done


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## ErichKeane (Sep 28, 2022)

So, did some work and finished the piece from yesterday, so started another casting, and afraid I messed it up good! Could use advise on work holding!

First, the two-at-90 degrees casting. I enlarged the lead screw relief, theb set it up to drill/tap for the mount for the lead screw on the other side:




Next, I drilled, tapped/reamed the holes for the gib screws and pin;




And, part complete!





So, next I decided to try the angle plate portion. This is a work holding nightmare. Thanks to the web, it doesn't really fit in my vise any way, but I started by just holding it by the web with some copper wire:



It is as far left as possible in this pic.  I was able to get 3 of the sides plus top milled, but left the other side to do on the shaper once I'm done, as I don't have a endmill that can do this in 1 pass.





Next, I started cutting the dovetail:



Things were going nicely, and I got within 150 thou of one of the dimensions, taking 50 thou full depth cuts, and all was going fine. Then, disaster:
	

		
			
		

		
	




The gouge is something that won't be a problem, but the loss of setup IS a problem!

I just don't have a good way of setting this back up in the vise. My ONLY idea at the moment is to put the big vise back on the shaper and hold it by the sides, and try to cut my first dovetail on a shaper. I've never done it successfully before, but I guess there is a first time for everyone?

Anyone have a better idea? What should I be thinking of?


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## ErichKeane (Sep 28, 2022)

I had another idea: I ordered some 3" tall soft-jaws, and am going to mill in a 'step', then use the two milled sides to hold it in place.  Hopefully being able to move it left most of the way will made a sufficient difference to make this worth-while.


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## ErichKeane (Sep 29, 2022)

Moved onto a different part today, and only had about an hour and a half. This is the longitudinal slide I accidentally didn't do before 

I got the outer shape done, did the dovetails, and moved onto the angle plate pivot bolt slot. The plans are wacky here, seemingly implying this should be a T nut and the dimensions are way off for it, so I came up with my own. Plunged with a 1/4" end mill, then widened each side 10 thou.

Then used a 5/8" endmill to make a .750 approx area for the washer. I would have used a .750 end mill, but I can't find my 3/4" r8 collet! Off to internet's to find one 



I still have to do gib screws/pin, lead screw mounting bolts, and t-slors, but the first two should take a short time tomorrow. AND my tslot cutter is supposed to come in this evening, so I can plan the slot around it.


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## ErichKeane (Sep 29, 2022)

Welp, I'm a big dummy   The T slot cutter I bought is a 10mm shank, so a 10mm R8 collet will be here early next week!  SO I'll have to put this part aside as well after another ~hr of work until next week.


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## rwm (Sep 30, 2022)

I had a cool idea about this project. Instead of using a complex gear drive, could you use an ELS type setup on this machine? Put an encoder on the spindle and a stepper on the gear blank.


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## MikeWi (Sep 30, 2022)

I don't get how a kit that's been around for so long would still have errors in the plans... That's just not right for them to leave it that way.


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## ErichKeane (Sep 30, 2022)

rwm said:


> I had a cool idea about this project. Instead of using a complex gear drive, could you use an ELS type setup on this machine? Put an encoder on the spindle and a stepper on the gear blank.



I'm sure you could! But there is something that feels wrong about having a gear hobber use an alternative to gears...   Also, as a computer guy: I don't trust them new-fangled-computers!



MikeWi said:


> I don't get how a kit that's been around for so long would still have errors in the plans... That's just not right for them to leave it that way.



I think you'll find this is the case in a LOT of casting kits.  Many of us are spoiled by PM Research/Stuart type stuff, but as soon as you get out of those, the plans are basically suggestions.  Basically what happens is someone decides they want to build some engine/machine/etc, so they cast some parts and go to work, designing as they go.  

After the fact, they realize others are interested, so they 1/2-ass a set of plans (sometimes just some weird photo-copies of old PM magazines!), and everyone after the fact has to figure it out.

In this case, this is a machine based on some old PM magazines that some casting-form-students of Gary Martin "designed".  For a while Gary sold ONLY the castings without plans, but a previous customer (also a local I think!) did the plans in exchange for a set of castings, and basically reverse-engineered the original, and drew it up.  The person who did so isn't a CAD expert (obvious by the complete lack of tolerances, and inconsistent references), and didn't try to WORK off the plans.  

There is definitely a level of attention in about 2/3 of the plans, but I suspect (based on the quality of the prints) that at one point he 'rushed' to finish, and filled in some gaps off of memory.  There is definitely evidence of design-changes that have been 2/3 changed in the plans.

I suspect that ever since, no one has given the feedback on this, and frankly, I'm unsure how many folks have actually completed this kit.  It is QUITE complex, and I see no evidence of any being completed other than the two/three machines in the above story.  Thats part of why I'm doing this thread!

I'm sort of keeping a log of what I suspect are errors, but I won't know if the errors are in the plans, or my interpretation of them.  A more ambitious version of me would be trying to draw what I make as I go, and I might do so eventually.


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## ErichKeane (Oct 5, 2022)

Alright, a very productive day today!

First, as mentioned before, I needed t slots on the top of one of the slides.  I started by cutting with a 3/8" endmill:



Then, my 10mm collet showed up and I was able to cut the t slots with the T cutter:



The slots are a bit "high" on the part, since I took about a week off  between those operations and forgot I left the 3/8" slot about 50 thou "high". It shouldn't matter, and I can make it up with the T nuts.

And the finished slide:




Next, I started with the work holding spindle. This part is similar to the one I scrapped, so I came up with an alternative for the lathe holding.

First, I put it on the mill to do the bottom. I used a wiggler to see the middle of the casting, since the casting line seemed about centered:



Next, I used a face mill to flatten the top, then a large 1" endmill to flatten the end face:


After that, I centered the pivot hole best I could, then drilled and reamed .250



The rotation slots seem to be an error on the plans, they say to make these 3/8", but they are for a 1/4" bolt, so I made them 1/4". I didn't think I could cut these from the top on a rotary table, nor could I figure out how to hold them that way, so I used the bolt circle setting on my DRO to plunge with a 1/64th over 1/4" endmill every 2 degrees:



Next, the lathe parts, which scared me. I ended up finding an angle plate that I had in the shop that had bolt holes that lined up to bolt the part to, which I could then use to square in the lathe. It took some packing to get the jaws to not crash, and 6 hands to get in place, but it held!

I ended up starting at about 20rpm, and as I went, got comfortable up to almost 100!



I cut the long inner bore first, which needs to fit a brass/bronze bushing from McMaster. I ended up being a wonderful press fit as speced!





I also had to do a larger bore for a bigger bushing, but only 1.5" through, not all the way. This one I ended up slightly oversized, so it is a "tight slip fit". I might end up loctiting it if necessary, but the shaft is supposed to squeeze these with the nut anyway.

Next, I turned down the outer spot where a clamp holds another part in this. I went a little long, but figured this will be good for lining things up.
	

		
			
		

		
	




I pressed in the small bushing with the shaper vise, and pressed the bigger one in with my hands, and this part is complete as well!





Whether I get shop time tomorrow is in the air, but next I'll probably work on the two parts that connect to the end of this work spindle body, as they are reasonablely easy and don't require special tooling I think.


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## ErichKeane (Oct 5, 2022)

One thing I found: My Mitutoyo DRO's bolt-circle is less featureful than the chinese one I had before!  It ONLY takes start angle, diameter, number of holes, and center.  NO end-angle!  So I had to set my start angle, and choose 180 holes, then give up when I hit enough!


----------



## ErichKeane (Oct 6, 2022)

Time was limited today, but I got two parts done in the nick of time 

First, I worked on the worm gear holder clamp. This was as easy as facing a couple of sides:




Then cutting a pair of slots and the main hole:




Next, just using a slitting saw to cut the clamp:



A quick facing cut, drill, and tap.


And, all done:



The next piece is the worm gear holder itself, which was just a bunch of squaring up, mixed with a couple of holes. I didn't get progress pictures, as I was coming against my time limit for the day:


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## rwm (Oct 6, 2022)

You do nice work. Hey, do you already own the gear train for use with this?


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## ErichKeane (Oct 6, 2022)

Thanks! I don't actually. I was thinking about just buying a hob in the right size, having the gear set 3d printed, then remaking them all in aluminum as a way of trying out the machine


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## rwm (Oct 6, 2022)

ErichKeane said:


> Thanks! I don't actually. I was thinking about just buying a hob in the right size, having the gear set 3d printed, then remaking them all in aluminum as a way of trying out the machine


Brilliant!


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## jrboldschool (Oct 7, 2022)

I'm new to this group, and your project definitely caught my eye. I've cut many gears using a specific gear cutter and dividing head, but I'm very interested to see how your gear hobber works out.


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## ErichKeane (Oct 7, 2022)

jrboldschool said:


> I'm new to this group, and your project definitely caught my eye. I've cut many gears using a specific gear cutter and dividing head, but I'm very interested to see how your gear hobber works out.


Thanks!  I've done a good amount of those as well, but always find it nerve wracking to get them right!  I'm hopeful these make gear cutting just trivial.


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## Ben17484 (Oct 7, 2022)

Very cool project and great work. Thanks for bringing us along! Keep the posts and pictures coming. I’ll certainly be following


Sent from my iPhone using Tapatalk


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## rwm (Oct 7, 2022)

Can we back track a little? I am confused as to how this device works. Can this cut DP gears as well as driven worm gears? How do you cut a straight gear with a hob that has a spiral pitch?


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## ErichKeane (Oct 7, 2022)

rwm said:


> Can we back track a little? I am confused as to how this device works. Can this cut DP gears as well as driven worm gears? How do you cut a straight gear with a hob that has a spiral pitch?


This can cut DP gears, but I dont know about worms.  I'm not sure how that would work?  

As far as how to cut a straight gear, I don't really 'get it' yet   I THINK the fact that the gear is spinning as well makes it work?  Here is a video of it running:


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## rwm (Oct 7, 2022)

I think I see now. The gear blank is angled with respect to the hob which cancels out the pitch of the hob.
If you wanted to make a gear to be driven by a worm you would just keep the blank at 90 deg and the pitch of the hob would have to match the pitch of the intended worm.




__





						Everything You Wanted to Know About Gear Hobbing - Federal Gear
					

If you know anything about gear manufacturing, you’re probably somewhat familiar with hobbing. But if you’re new to the game, it may sound like a strange term. Hobbing is an important machining process that allows manufacturers like Federal Gear to cut precision gears from raw materials. It’s...



					fg-machine.com


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## ErichKeane (Oct 7, 2022)

rwm said:


> I think I see now. The gear blank is angled with respect to the hob which cancels out the pitch of the hob.
> If you wanted to make a gear to be driven by a worm you would just keep the blank at 90 deg and the pitch of the hob would have to match the pitch of the intended worm.
> 
> 
> ...


Ah, that makes sense!

As designed, I don't think this could do worms, I'd have to do that on my lathe   BUT, it should be able to make enough gears for itself, and kill my time as a shop project, so it'll accomplish my goals at least  

Fortunately, there is a local group for model machinists (I haven't got out to a meeting yet!), where both the designer and plans maker are members, so hopefully I'll have resources to get the answers I need.

I STILL have no idea how the lead-screws work for any of the three axes (though 2 are the same!), but that is a problem for 'later Erich'.  

The nice part is I'm getting close on castings.  Once I get the angle plate, I'll have what I consider the 'main tower' done (though lead-screw brackets I'm holding off until I have the lead screws made, as well as the feed-gear quadrant which I'm holding off until the lead-screw bracket is done!).  

I still need a replacement hobb-spindle housing casting, which after I do THAT, i can do the quadrant for it, and that would be all the castings.



ONE BIG QUESTION I haven't answered for myself:  The plans are designed around an NMTB-20 for the hobb and work spindle centers.   I don't seem to be able to find one of these AT ALL, they are basically unobtainable from what it looks like.  They DO have drive-dogs, which are nice.

I DID find an old forum post at one point, where the author of the plans mentions that the 'original' (this is a modified version of the one @vtcnc is working on!) was based around MT2.  This ends up making a couple of parts a little simpler, lets me use a reamer to get the taper, AND makes for cheap MT2 'blanks' as my tool/hobb holders, which is very tempting.    So I'm leaning THAT way.

A SECOND (smaller) QUESTION: Is how to figure out which gear sizes I need, and where to put them to make stuff work.

AND A THIRD, smaller/later QUESTION: What sort of motor I see myself using for this.  I went to the electronics-scrap store yesterday to see what they had, and there wasn't anything great (though I DID impulse buy an O-scope, so....).  I THINK a treadmill motor is going to be too big, and I don't have a good idea of what size motor to use...

Basically, I'm leaving all of those questions for "later Erich" at the moment, but I figured folks here might have a useful opinion on each!


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## rwm (Oct 7, 2022)

I wasn't actually considering making worm gears with it but rather the gear driven by the worm. A worm is essentially a hob without cutting teeth.


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## ErichKeane (Oct 11, 2022)

So a bit of progress today, but a bit of a mess up too, which hopefully I can fix easy enough.

First, I installed the new aluminum tall jaws I ordered. There was zero machining done on these, they are as extruded! Oh well, flat/straight enough, and I'll mill them like soft jaws instead.




I faced the top, then tightened the vice and ran a 5/8" endmill down the center, 1/4" deep.


	

		
			
		

		
	
These were enough to hold the part firmly enough. I had previously flattened the sides, but I wasn't able to get the top face closer than about 10thou. So, I faced the top down a bit:



Then, in the same setup, I cut the dovetails finally to size:



I screwed up here and removed all of it from the vise and swapped the jaws.... Then I noticed that I forgot the lead screw relief, so I had to swap the jaws back in, set it up and cut it out with a ball endmill. I had to plunge cut, since the casting didn't have the space cast out of it this time:




Once everything was back and the vise was re-indicated in, I faced the bottom. I had quite a bit to take off, but left it thick:


As you can see, most of my crash earlier came out, but not all! There is a tiny fingernail sized sliver left:



Here is where I messed up. I found my center point and started drilling. BUT I thought this was for the brass nut, instead of the 1/4-20 hole. I got a 1/2"+ sized hole before I realized it.

I opted to patch it with a 9/16-18 threaded piece, as I had that tap handy! It power tapped with only the 1/2" drill bit, which was fortunate as otherwise I would have needed the boring head.

Next, I grabbed a piece of 12L14 I had that was 5/8", turned it down a bit under 9/16", and single pointed some threads. I didn't have a nut to test it with, but I figured I'd press my luck cutting by eye (basically until the blue got razor thin).




Fortunately it fit just right! I used a ton of loctite red to lock it into the hole. I called it a night or give the loctite time to cure, and for me to stop being a dunce.


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## ErichKeane (Oct 12, 2022)

Alright, busy day! First I used an end mill plunge cutting through my repair to get it just below flush:




Then drilled and tapped 1/4-20" for it's mounting bolt:



I wasn't confident I could get this on the rotary table in a stiff enough way, so I once again used the bolt circle tool, cutting every 2.5 degrees:



Then, a file and some elbow grease got the bolt sliding. I'll probably spend a few more minutes on this at one point:



After that, I cut the area for the nut like before, and that is all there is to this part!




Next, the lead screw bracket castings:
	

		
			
		

		
	



I cut them apart, then milled the top and back.



I was not convinced that the lead screw setup will actually WORK as specified, so I pulled up FreeCAD and modeled it.

I realized that my mental model of these parts was reversed, so good thing I modeled before cutting!

I also think that I know how to modify the plans to make two of the three leadscrews work!

AND, enough that I can cut these castings. BUT that is for another day.


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## ErichKeane (Oct 12, 2022)

SO, I've attached a render of the lead-screw extension + everything else in case it helps anyone.  It is a .html canvas, so anyone with a browser can look around!  You can see the color scheme in the upper right of the controls.

RED is the lead-screw extension (which you'll see me make soon enough!), which goes on the end of the lead screw to attach to the handle.

PURPLE is the two thrust bearing stacks (bearing + 2 washers), but I didn't break them up.

The see-thru YELLOW is the lead screw mount castings that I just started on above.  

GREY see-thru is the 'dial' which you can read.  

light/see-thru purple is the dial-sleeve, which is keyed to the shaft (not CAD'ed).  I chose to lengthen this piece by .075", since otherwise it was shorter than the middle-radius of the lead-screw-extension, and the handle (not pictured, but goes on the lead-screw-extension's smaller diameter) would not be able to tension the bearings.  I Think this is another mistake in the plans.

Brown is a washer, and teal is a nut to tension the dial on the dial-sleeve.  I NOTE that the dimensions on the nut are basically all missing, so I chose .250 for now, but I suspect i'll have to make it shorter at one point.

BUT, now I know enough about how it goes together to actually make the cast parts


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## silverhawk (Oct 13, 2022)

Nice recovery on the 1/2" hole for the 1/4"-20 thread! Good progress!

Sent from my SM-G970U using Tapatalk


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## brino (Oct 13, 2022)

Erich,

Was that "html canvas" file made with FreeCad too?
That looks very useful for sharing design concepts........

Thanks,
Brian


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## ErichKeane (Oct 13, 2022)

brino said:


> Erich,
> 
> Was that "html canvas" file made with FreeCad too?
> That looks very useful for sharing design concepts........
> ...


Yes it was!  I have FreeCAD 0.20, and it was an option on the 'export' menu!


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## TorontoBuilder (Oct 13, 2022)

ErichKeane said:


> The hobber looks pretty nice! The plans are 5/10, but the castings are beautiful. I'd suggest getting it now so you can follow along with my build
> 
> If you can convince a few others, I could talk Gary into a group buy.



I'm late to the party, but I have been eyeing the hobber castings for years since I make etching presses with gear trains I keep making from scratch the hard way.

I also want the Quorn, UPT and die filer castings.. so I could basically do my own group buy...  is there a forum for organizing such things?


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## ErichKeane (Oct 13, 2022)

TorontoBuilder said:


> I'm late to the party, but I have been eyeing the hobber castings for years since I make etching presses with gear trains I keep making from scratch the hard way.
> 
> I also want the Quorn, UPT and die filer castings.. so I could basically do my own group buy...  is there a forum for organizing such things?


If you get in touch with Gary, I'm sure he could make you a deal directly!  @vtcnc started a thread for a group buy at one point I thought, but I can't seem to find it.  I don't know how much interest there was, but I'm sure if you're wanting that many things you can start a landslide


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## TorontoBuilder (Oct 13, 2022)

ErichKeane said:


> If you get in touch with Gary, I'm sure he could make you a deal directly!  @vtcnc started a thread for a group buy at one point I thought, but I can't seem to find it.  I don't know how much interest there was, but I'm sure if you're wanting that many things you can start a landslide



If I stick to Southern Ontario there are plenty of hobby machinists so I potentially could put something together. But I fear that i'd still only get a couple of people interested.


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## ErichKeane (Oct 14, 2022)

Alright, well, I got busy yesterday and didn't post my update, so today is a double feature!

First, for these lead screw brackets, I flattened the outside to thickness:



Next, I found the center of the boss best I could, since the rest of the measurements are based on that:



Finally, I drilled and reamed the lead screw hole, and used the DRO for the mounting holes. The crossfeed mount is a little different (since a quadrant attaches to it), so those holes also got countersunk. One gotcha: 2 of them are 400 thou between the mount holes and leadscrews, the other is .325.  the plans say match drill, so this is where I had to pay attention!
	

		
			
		

		
	




After that, a test fit with these on the whole 3 axis setup:






I made a mandrel in the lathe with a 3/8" center to mount these so I could turn the OD.  While drilling the end, I untwisted a #7 drill!



And here is the big one mounted on the mandrel. The OD mattered, and the depth didn't as much, but all are turned the same way. I used some bearing retainer loctite which stickied up just enough in 10 mins to hold the part still.




After doing all 3, here they are:



That was the end of yesterday!

Today, I needed to do the back feature, where a thrust bearing is sandwiched between the mount and the lead screw shoulder. I was able to get them setup easily enough in the 4 jaw, and bored it out, a bit more than .300 deep, and .800 around for clearance. The stack up is only .265, so there is plenty of depth.



After all 3;



Then, I started on another part: the feed quadrant, which holds gears to power the gear through the cutter. First operation was a but precarious, but I was able to flatten it well enough. My casting was a bit pretzelly, so in the end I end up about 40 thou too thin, but hopefully that doesn't cause problems.
	

		
			
		

		
	




Next, I flipped it over onto a fixture plate I made a while back, and milled the other side flat, moving clamps mid way through:




I used the boring head to get a tight fit on the lead screw mount:



Finally, drilled the clamp hole, used the cut off wheel to make it a clamp, then went back and clearance drilled the top, then tapped:





And, done, clamped onto the mating part:
	

		
			
		

		
	




And, that's it! All the castings in the "main tower", and all but 2 of the castings total!  One of which I need a replacement, the other of which is another quadrant that attaches to that (so I have some adjustments I can use cutting it differently).

I'm on the fence whether I intend to drive the hour each way to pick up the replacement casting right away, or if I want to just start making the rest of the parts to assemble the main tower. What do you all think?


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## ErichKeane (Oct 19, 2022)

A little more work today! First, I bolted the L bracket to the frame, I had to widen one of the bolt holes in the bracket though, because my hand drilling wasn't accurate enough.




Next, I went to put the bottom slides dovetail in place, with the keystock in place. I discovered that I machined the keyslot wrong on the dovetailed piece!  I put it in line with the bolt holes instead of about 63 thou further away.

I put this back on the mill and slotted the base bolt holes an additional 75 thou. They look a little oddly shaped because I didn't use the chamfer tool on it.



After that, it bolts on fine!





I actually then took it right off to put a little relief in all the slides, like this. The gib is held in place with the help of a pin, and this will let me be less accurate installing the pin to depth.



Speaking of gibs, time to make them! 1/2" by 1/8" brass cut into 6" pieces (quite a bit too long, but I'll cut them to size later), and a tilted mill head cleaned up the first side.



To get the other side, I milled a slightly thinner piece of aluminum with the same angle, then used it as a parallel. I ended up loctiting them together because I had a problem with them sliding.






Next, I had to drill the pin hole in the gib. After quite a few failed attempts, it took me too long to realize I already had a gib clamp! I ran the 3/16" endmill down the hole and cut it! You can see scars on this one from my failed attempts.






And that's it for today! I'll continue assembling the tower, making the parts needed to do so as I go!


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## ErichKeane (Oct 24, 2022)

Since my last post, I went and picked up a replacement for the casting I messed up.

AND, decided on my gear setup based on a hob I picked up on ebay:
16,20,24,25,28, 30,32,36,38,40,44,45,46,48,50,52,54,56,60,64,65,70,75, 80

From THERE, I did a bunch of programming (I'm a C++ Compiler engineer in my day job!) to try to figure out which gear sets I would need to get printed in order to be able to make 2 of each of those gears.  I found a bit more than 400+ candidates and cut that list down as much as I could (limited valid gear trains by 'should mesh correctly' as well!), and have arbitrarily picked:

24 28 38 40 44 46 50 52

In doing the running, there are about 2.2 million combinations of 'gear trains' that result in one of the target gears (and are possible as best as I can tell!).  I picked that set since it has sufficiently 'large' sets of gears that I think it can reach all the way across.

With those, I was able to come up with the attached document of 'how to get to all 24 gears' (and make a max of 2 of each!).  

A gear-train has an 'input' gear, 2 'quadrant' gear-pairs, and an 'output' gear (plus there is a 20:1 reduction at the end!).

A Quadrant where both items of the 'pair' are the same are just a single-gear, and I represented them internally as a pair.

BUT 8 gears was the minimum I could find (though I THOUGHT there were some options for something like 16,16,16,20 when I was just getting started, but I cannot seem to reproduce that again!).


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## ErichKeane (Oct 24, 2022)

Ah, woops!  I found my 'bug' I guess on the doing-it-with-only-4-starters.  It seems it requires duplicates!  At one point when programming (it is a VERY large search space!), I was trying to limit the search space and ended up disallowing duplicate 3d printed gears.  

BUT there are a whole bunch that apparently let me get away with only 4 printed gears!


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## ErichKeane (Oct 27, 2022)

So a few disorganized/all over the place sorta days, but not much to show of it.

I got all the lead screws cut, cleaned up, and turned down for a press fit extension. The extensions were then cut and drilled and press fit into place. 2 of the 3 got loctite, 1 I forgot.

I also got the replacement hob spindle housing casting, so today I did all the milling operations on that. I have to do the bores and area for the quadrant to mount, but I'm back to where I screwed it up last time.


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## ErichKeane (Nov 1, 2022)

A little more work done... I had a few discouraging days of not getting much done, and having to restart/etc, so I had a bit of a "reset" day. Additionally, a bigger angle plate came, which means I can do the hobber body, which means I can get the 4 jaw off the lathe 

First, I decided to drill/tap my handles. Work holding was awful, but it worked. I got these from LMS, since the handles specified in the plans no longer exist.





The set screw is just an 8-32 I had left over from the gib screws, so I'll have to shorten them or buy shorter ones.

Next, I decided to continue working on the rest of the castings. I messed up this hob spindle housing last time, so I picked up a cheap shop made angle plate for this time.




I did some marking up, and got 4 holes drilled/tapped to use the mount holes to bolt it securely on the plate.



And here it is on the lathe. I had to bore the center to about 1.5":



Next, there is a second bore for the bearing on this side. Plans say slip fit, and I think I got it perfectly:



Finally, I had to cut the area for the quadrant clamp. Again, uneventful:



I have 2 things to do on the other side, which I might just do on the mill, but at least this setup is done.


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## ErichKeane (Nov 2, 2022)

So, I am travelling next week, so I wanted to get to a good stopping point. SO, I worked a TON this afternoon.

First was finishing up the hobber spindle housing. I need a bore for some bearings, plus some holes for the clamp that holds the bearings in place:




A boring head + the DRO made short work of those things

Next, in order to get it to bolt down more nicely, I flattened the mounting flange:




After that, a test fit:



Next,I need a quadrant for the hobber side. I used my fixture plate to flatten it best I could. The dimensions in the plans for thickness weren't possible due to the castings thickness, so I just did my best to get it cleaned up here.




I used the fixture plate for a everything on the part I could, including the big bore. I got a bit of chatter, plus idiot marked my fixture plate, but was able to clean it up enough. The big bore is a touch oversized, but it works out in the end.

Finally, I had to make the clamp, which was a facing op, drill, tap, counter drill, and slitting saw. The setup is a little scary, but I took it easy and had no problems.




So, that is ALL the castings complete! As far as I know, there are no operations left for those!





Next I think I'm going to get the lead screws squared away. Off camera,I cut them to length and glued on an extension, so I have to turn those plus everything they goes on it.

After that of course, is the entirety of the drive line, which will obviously be the more time consuming half if this project. I might paint the castings soon though, just to get them protected.


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## ErichKeane (Nov 3, 2022)

Figuring I won't have any more time before I leave, and encouraged by some rustish stains on some of the castings, today was paint prep and prime day.

I disassembled and laquor thinnered everything, marking parts that needed to go back together right.

A bunch of tape off plus some grey primer should get it ready.

I intend to paint it Ace Rust Guard Almond Gloss, but I'll have to wait a few days for that.


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## ErichKeane (Nov 24, 2022)

Well, so... the paint went REALLY bad.  I started with the grey brush-on primer, which didn't look awful, I did 2 coats, and it seemed to stick well.  Then I did 3+ brush-on almond color, and it was lumpy, brush-strokey, patchy, and awful.  I didn't bother taking pictures.

SO, I just finished using paint-remover on ALL the surfaces, which caused some surface rust, so I wire brushed off all of that, cleaned everything, re-chemical cleaned it, and did what I should have in teh first place, I sprayed primer on everything.  About 1/4 of the parts also got their 1st coat of the almond paint (spray on this time!) and they seem to look alright.  Between my trip plus the holidays plus this set-back, not much has happened on this project in a while


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## brino (Nov 26, 2022)

Hi All,

Back in post #36 of this thread Erich said:


ErichKeane said:


> I was thinking about just buying a hob in the right size, having the gear set 3d printed, then remaking them all in aluminum as a way of trying out the machine



I've been enjoying this thread so much that I messaged Erich and offered to 3D-print the set of gears he needs.
No charge, I just want two things i) to keep his fantastic project going, and ii) some honest feedback on how they work out.

Erich produced a list of the eight gears that should allow him to generate all the gears he needs.

The tooth counts required are:  38 40 44 46 50 52 56 60

the rest of the specs were given as:
14.5 Pressure Angle
20 Diametrical Pitch
3/8" thickness
5/8" bore with a 1/8" key (i can cut the key with a file, or come up with another solution if need be!).

Here's some pictures of the gears:









I printed them solid (100% infill), so that the required key way can be cut with a broach.

Just for interest, these eight gears used 110g or 16m (3.9 oz. or 52.5 feet) of the 3mm dia. PLA filament.
I got that 1kg spool for ~$25 (including tax), so all eight gears were only about $2.75 in materials.
Shipping them to Erich will likely cost a little more than that (not complaining, just saying!)

Erich I do have a broach set, if you confirm the specs of the key-way you need (is it 1/8" x 1/8"?) I can see if I have the appropriate broach and if so I can cut them before sending them. If you are setup to cut them yourself, then I can get them in the mail. Just add your address to that private message.

Brian


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## ErichKeane (Nov 26, 2022)

I actually picked up the right broach already, so you can just ship them if you'd like.  The keyway is 1/8x1/8, but I have purchased the broach and bushing (Just have to hope my arbor press is up to the task!).

I'll PM you the address!


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## brino (Nov 26, 2022)

ErichKeane said:


> Just have to hope my arbor press is up to the task!



LOL!


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## rwm (Nov 27, 2022)

So cool. I love the idea of cutting these in aluminum now.


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## Winegrower (Nov 27, 2022)

You can get a set of 8 cutters with these DP20 specs for about $76 on eBay.   I have purchased a Mod 1.5 set that I used for some Delrin gears…aluminum seemed like it would be no problem.


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## ErichKeane (Nov 27, 2022)

Winegrower said:


> You can get a set of 8 cutters with these DP20 specs for about $76 on eBay.   I have purchased a Mod 1.5 set that I used for some Delrin gears…aluminum seemed like it would be no problem.


You found 8 gear hobbers for $76?  I picked up the cheapest one I could find on ebay (hence 14.5 PA/DP20) and it came out to $100 for one!


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## Winegrower (Nov 27, 2022)

ErichKeane said:


> You found 8 gear hobbers for $76? I picked up the cheapest one I could find on ebay (hence 14.5 PA/DP20) and it came out to $100 for one!



Yes, quite a few of them...I searched on gear cutter 20DP.    For a set of 8, $65 plus $5 shipping.   So I was inaccurate.









						8Pcs/Set DP20 DP12 Involute Gear Cutters HSS Gear Cutter PA14-1/2 14.5° degree  | eBay
					

Find many great new & used options and get the best deals for 8Pcs/Set DP20 DP12 Involute Gear Cutters HSS Gear Cutter PA14-1/2 14.5° degree at the best online prices at eBay! Free shipping for many products!



					www.ebay.com


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## ErichKeane (Nov 27, 2022)

Winegrower said:


> Yes, quite a few of them...I searched on gear cutter 20DP.    For a set of 8, $65 plus $5 shipping.   So I was inaccurate.
> 
> 
> 
> ...


That's not gear hobbers though, those are approximated gear cutters. Gear hobbers look like these : https://www.ebay.com/itm/3636309326...H8d09NDpOAvztPK9HzlDkD-8QSOleH4gaAvMXEALw_wcB

A single cutter will cut ALL numbers of teeth exactly, rather than approximately, since they use the rotation of the gear to cut involutes correctly.

The intent of a hobbing machine is to use these gear hobbers to cut the gears "correctly" and in a reasonably automated way.


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## Winegrower (Nov 27, 2022)

I see.   Sorry to get you excited.  These cutters are what would make Brino’s spur gears.   You’re in a different league!


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## ErichKeane (Nov 27, 2022)

Winegrower said:


> I see.   Sorry to get you excited.  These cutters are what would make Brino’s spur gears.   You’re in a different league!


Ah, I see what you mean!  Yeah, I considered just making gears that way to 'start off' the hobber (I have a couple of those cutters as well), but personally feared they would result in me being less motivated to make a whole set with the hobber if I had a couple of aluminum ones already   Part of the idea is that the plastic ones would be 'good enough to get going, but suspicious enough that I wouldn't consider them part of a full set of gears' to motivate me to cut all the aluminum ones on the hobber!

One of the nice parts of this hobber though, is once you set the angle and power feed right, you can leave it to its own devices for a while and let it cut a couple at time!  I intend to leave the spindle long enough to let me cut 3 gears at a time, so I can make myself a set of 2-of-each (useful due to the length of the gear train!), and perhaps end up with an extra set to pass onto someone.

The DOWNSIDE of course to any hobber is the cost of the hob cutters, but it is only 1 per PA/DP combo, and I figure I can self-standardize on the size I got for a while if need-be.


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## f350ca (Nov 27, 2022)

Wonder if you could make them. 
I make a cheat one, basically a hob without the spiral. The centre set of teeth cut the tooth while the ones above and below relieve the adjacent teeth. Work fine one small gears,
I cut the tooth form at 14 1/2 pressure angle, basically an acme thread, by plunging straight in. You should be able to determine the pitch and cut the rack form then for the teeth as I do on the mill.







Made from drill rod then hardened, cutting bronze I don't bother to temper them.

Greg


----------



## ErichKeane (Nov 27, 2022)

f350ca said:


> Wonder if you could make them.
> I make a cheat one, basically a hob without the spiral. The centre set of teeth cut the tooth while the ones above and below relieve the adjacent teeth. Work fine one small gears,
> I cut the tooth form at 14 1/2 pressure angle, basically an acme thread, by plunging straight in. You should be able to determine the pitch and cut the rack form then for the teeth as I do on the mill.
> 
> ...


Yeah, some folks do home-made gear hobs that way. This project was a little too much work already, so having to make my own hob was a bridge too far


----------



## ErichKeane (Dec 1, 2022)

Ok, so I got some work done!  A while back, I was able to get the parts all cleaned up and spray-primed, so first task was the color coat.  Through the afternoon, I sprayed 2 coats, which will hopefully be all I need to do.  I noticed all the tapped/drilled holes are pretty messy wiht paint/paint-stripper/overspray, so I'll likely need to clean those up as I re-assemble:




Next, I did some quick thumb nuts, which were just a turn to diameter, drill/tap 5/8-18, knurl, and part.  Hardest part was fixing the threads after parting them off 




These nuts will be used to tighten things on the lead screw collar part that I'm making next.  The plans dont have a thickness, so I thought 200 thou was a good look.  Worst case, they are easy enough to re-make.  I ended up using some hot-rolled I had around the shop for those and the next part.

Onto the collars!  These will end up holding the dial/gears on the leadscrew, and interface with one side of the thrust bearing.  This will be more obvious when I assemble these.  First, I found some scrap A36 from some knurling practice, and turned the OD down to .800.






Next, turned and polished the smaller diameter down to .625.




Then, a quick single-point.  The threads look ugly in this picture, but they were actually quite nice cleaned up.




Finally, drilled, and reamed for 3/8" to fit on the lead screw extensions:




Flipped around, and faced to length:




FINALLY, I had to broach the inside.  I'll eventually have to cut an external keyway as well, but I want to see how keep the larger broach for the 5/8" makes it, so I can cut it to fit.  One thing I DID have a problem with: The little 1-ton arbor press I was given at one point is REALLY not up to the task!  It can only JUST handle the 1/8"-A broach length, and even then I couldn't use the bottom plate, I had to drill a hole in some aluminum plate to even be able to use it.

I'm going to have to come up with a different solution with the bigger broach unfortunately, which I was hoping I wouldn't have to do.

In the end, it 'worked' well enough:


----------



## rwm (Dec 2, 2022)

You could broach it on your lathe maybe? How long is the keyway?


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## ErichKeane (Dec 2, 2022)

rwm said:


> You could broach it on your lathe maybe? How long is the keyway?


The larger keys are 5/8 diameter, and 1/8" wide. Though, if I was going to cut those, I would probably just do it in the shaper.

I got the broaches because these are pretty tiny.


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## dkemppai (Dec 5, 2022)

ErichKeane said:


> The little 1-ton arbor press I was given at one point is REALLY not up to the task!  It can only JUST handle the 1/8"-A broach length, and even then I couldn't use the bottom plate, I had to drill a hole in some aluminum plate to even be able to use it.



Just a thought... 








						DAKE CORPORATION 972200 Hydraulic Press,Manual,10 tons  | eBay
					

Find many great new & used options and get the best deals for DAKE CORPORATION 972200 Hydraulic Press,Manual,10 tons at the best online prices at eBay! Free shipping for many products!



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Things about this are so much better than the discount tool supplier designs with bottle jack. Being a small bench top unit, it gets used more than I though it would.


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## ErichKeane (Dec 5, 2022)

dkemppai said:


> Just a thought...
> 
> 
> 
> ...


Thats neat!  Though quite expensive to ship.  I'll have to see if there is anywhere local that sells stuff like that.


----------



## dkemppai (Dec 5, 2022)

ErichKeane said:


> Thats neat!  Though quite expensive to ship.  I'll have to see if there is anywhere local that sells stuff like that.



165lbs. It's not a light weight. Mine shipped freight...


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## rwm (Dec 5, 2022)

Hydraulic presses are not ideal for broaching.


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## ErichKeane (Dec 5, 2022)

rwm said:


> Hydraulic presses are not ideal for broaching.


Yeah, but sadly arbor presses big enough for broaching aren't ideal for budgets haha


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## WobblyHand (Dec 5, 2022)

ErichKeane said:


> Yeah, but sadly arbor presses big enough for broaching aren't ideal for budgets haha


I'm sure it can be done hydraulically, but it is not safe.  You will have no idea if the broach is about to explode on you.  The flying pieces could hurt or kill you.  Broaching with an arbor press requires feeling that the broach is cutting properly.  If it isn't, you need to back off and readjust it.  If I were to consider doing it with a hydraulic press, I'd put up a really thick ballistic grade barrier between myself and the press.  That's just me talking with not that many broaches under my belt.  I have a 3T arbor press.  Your experience may differ.


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## ErichKeane (Dec 5, 2022)

WobblyHand said:


> I'm sure it can be done hydraulically, but it is not safe.  You will have no idea if the broach is about to explode on you.  The flying pieces could hurt or kill you.  Broaching with an arbor press requires feeling that the broach is cutting properly.  If it isn't, you need to back off and readjust it.  If I were to consider doing it with a hydraulic press, I'd put up a really thick ballistic grade barrier between myself and the press.  That's just me talking with not that many broaches under my belt.  I have a 3T arbor press.  Your experience may differ.


Well, yall jerks have lived up to your reputataion, ya'll don't disappoint.  I ordered the Vevor 3T (and a flammables cabinet), which looks like it'll be plenty big.  I'll have to weld up a stand, but that should be easy enough.


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## WobblyHand (Dec 5, 2022)

ErichKeane said:


> Well, yall jerks have lived up to your reputataion, ya'll don't disappoint.  I ordered the Vevor 3T (and a flammables cabinet), which looks like it'll be plenty big.  I'll have to weld up a stand, but that should be easy enough.


I'm disappointed you feel that way and apologize if I was overbearing with my opinion.  I admire your work and progress on this project.


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## ErichKeane (Dec 5, 2022)

WobblyHand said:


> I'm disappointed you feel that way and apologize if I was overbearing with my opinion.  I admire your work and progress on this project.


Oh, no, I'm joking.  You were right, an arbor press is a better idea.  Just the (self-embraced) 'reputation' of this forum is "The solution to all problems is to buy more tools!" that I was teasing you for   I feel like we are the world's worst support group


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## Winegrower (Dec 6, 2022)

WobblyHand said:


> I'm sure it can be done hydraulically, but it is not safe. You will have no idea if the broach is about to explode on you. The flying pieces could hurt or kill you. Broaching with an arbor press requires feeling that the broach is cutting properly. If it isn't, you need to back off and readjust it.


I see this opinion expressed here frequently, and I wonder how much actual experience is talking.   I have broached many keyways with both a 20T HF press and a small bench arbor press.   It is very feasible and necessary to sense the pressure with both tools…not just that, there’s also an alignment issue, and keeping an eye on the shims.  If you can’t do all that, it matters not which press you have...you will have trouble, maybe get hurt.


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## WobblyHand (Dec 6, 2022)

Winegrower said:


> I see this opinion expressed here frequently, and I wonder how much actual experience is talking.   I have broached many keyways with both a 20T HF press and a small bench arbor press.   It is very feasible and necessary to sense the pressure with both tools…not just that, there’s also an alignment issue, and keeping an eye on the shims.  If you can’t do all that, it matters not which press you have...you will have trouble, maybe get hurt.


 It's surprisingly easy for the broach to hang or get stuck due to shims falling out or the broach getting a bit misaligned.  Manually, it's obvious when this happens, because the level of effort increases a lot.  

Of course you can do this hydraulically, if you are careful and always on your game.  I'm usually careful, but can't say that I'm always on my game.  So I take it slower, using an arbor press, where there's more obvious signs that the broach is cutting correctly or going awry.  It works for me.


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## WobblyHand (Dec 6, 2022)

ErichKeane said:


> Oh, no, I'm joking.  You were right, an arbor press is a better idea.  Just the (self-embraced) 'reputation' of this forum is "The solution to all problems is to buy more tools!" that I was teasing you for   I feel like we are the world's worst support group


That's how I used to feel about HM, but it seems that the Borg has consumed me.  "We" are quite the tool enabling bunch.


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## dkemppai (Dec 6, 2022)

ErichKeane said:


> Yeah, but sadly arbor presses big enough for broaching aren't ideal for budgets haha


I completely agree.

I also agree hydraulic presses are not ideal. However, with the press linked, the cylinder is threaded into a plate bolted to the upper support. There is ZERO play. It's also very square to everything, unlike those budget tool bottle jack/bottle hack presses. There is a pressure/force gauge to monitor what's going on also. Still not as good as feeling the handle of an arbor press, but SO much better than an HF press. 
And all things considered, this hydraulic press is still safer than using a sledge hammer to drive that broach! 

Edit: I guess since you're making a gear hobbing machine, getting something better to drive broaches is probably pretty high up on the list . If that's a bigger arbor press, this machine would probably justify it...

Something just crossed my mind. Once you get the machine up and running I could use a couple of brass gears for my old sheldon lathe, if you're up for a small paying job...


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## MikeWi (Dec 6, 2022)

ErichKeane said:


> I feel like we are the world's worst support group


But we _are _the worlds best enablers!


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## dkemppai (Dec 6, 2022)

MikeWi said:


> But we _are _the worlds best enablers!


Hand raised, "Hi, My Name is Dan. And I'm a tooloholic". 

(No offence to anyone in any actual program. Just my sense of humor... )


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## ErichKeane (Dec 6, 2022)

dkemppai said:


> I completely agree.
> 
> I also agree hydraulic presses are not ideal. However, with the press linked, the cylinder is threaded into a plate bolted to the upper support. There is ZERO play. It's also very square to everything, unlike those budget tool bottle jack/bottle hack presses. There is a pressure/force gauge to monitor what's going on also. Still not as good as feeling the handle of an arbor press, but SO much better than an HF press.
> And all things considered, this hydraulic press is still safer than using a sledge hammer to drive that broach!
> ...



Yeah, I figure I'm going to be doing a lot of 5/8" bores with a keyway while making this (I want to make a set of ~20 gears with this for itself), so I want it to be as low-effort as possible here.  I'd be up for making those gears for you though once this machine is up and running!  It might be a while though, I think I'm approaching the 'devil in the details' part of this project (PLUS, the 'its too cold to start a fire in teh shop, I'm going to stay on the couch today part of the year)   But if you're up for the wait, I'm up for it!



MikeWi said:


> But we _are _the worlds best enablers!



Don't I  know it!



dkemppai said:


> Hand raised, "Hi, My Name is Dan. And I'm a tooloholic".
> 
> (No offence to anyone in any actual program. Just my sense of humor... )



I too was trying to find a way to reference a 12 step program, except we're the inverse


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## dkemppai (Dec 6, 2022)

ErichKeane said:


> But if you're up for the wait, I'm up for it!


This thing has needed new brass gears for way longer than I've owned it. Probably 30+ years if I had to guess! So, no rush. Just another of those 'roundtoit projects...



ErichKeane said:


> I too was trying to find a way to reference a 12 step program, except we're the inverse


I'm only at step 1. I don't think I'll get beyond that...   ...I think I'm ok with that.


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## rwm (Dec 6, 2022)

Buying an arbor press is like...step 10 I think. 1.Drill Press 2.Lathe 3.Mill ....I know 8 is a surface grinder?


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## ErichKeane (Dec 6, 2022)

rwm said:


> Buying an arbor press is like...step 10 I think. 1.Drill Press 2.Lathe 3.Mill ....I know 8 is a surface grinder?


Haha!  Well, I'm skipping around I guess, I don't have a drill press in my shop, but have the arbor press and surface grinder.  What step is a shaper?  Because I'm on my 2nd of one of those


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## FOMOGO (Dec 6, 2022)

Next, obviously. It would make those key-ways in short order. I'm heading down the mountain in a day or two, to feed the habit. Cheers, Mike



ErichKeane said:


> Haha!  Well, I'm skipping around I guess, I don't have a drill press in my shop, but have the arbor press and surface grinder.  What step is a shaper?  Because I'm on my 2nd of one of those


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## brino (Dec 6, 2022)

WobblyHand said:


> That's how I used to feel about HM, but it seems that the Borg has consumed me. "We" are quite the tool enabling bunch.




You will be assimilated!


----------



## ErichKeane (Dec 6, 2022)

FOMOGO said:


> Next, obviously. It would make those key-ways in short order. I'm heading down the mountain in a day or two, to feed the habit. Cheers, Mike


Heh, i considered using the shaper for the key ways, and I've done so in the past!  While MUCH cheaper to do, its also somewhat time consuming, particularly for 20+gears.


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## rwm (Dec 6, 2022)

You can make anything with a shaper, except money.


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## ErichKeane (Dec 6, 2022)

rwm said:


> You can make anything with a shaper, except money.


So I've heard!  I've definitely made some nice stuff with it   Though i WILL say, a shaped flat surface with a shearing bit is the nicest finish I've ever seen, I'm surprised folks won't pay extra money for that rather than the 1/2 circles on all our tooling!


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## dkemppai (Dec 6, 2022)

rwm said:


> You can make anything with a shaper, except money.


No, I made a lot when I sold mine! Lol.


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## dkemppai (Dec 6, 2022)

ErichKeane said:


> So I've heard!  I've definitely made some nice stuff with it   Though i WILL say, a shaped flat surface with a shearing bit is the nicest finish I've ever seen, I'm surprised folks won't pay extra money for that rather than the 1/2 circles on all our tooling!


The Moore book, Foundations of Mechanical accuracy states that a precision surface plate is best done with a single point with a planer. Of course those guys are scraping that down to single digit millionths of an inch stupid kinds of ranges. 

I know for a fact that milling and even grinding can induce residual stress in the material.  Etch a surface ground then mirror finished martensitic stainless tool steel some time. After a Grind, finish, and etch and the surface grinder marks show up again. I'm sure that's the residual stresses showing up in the etch. Like of how shot peeing increases a parts strength by inducing residual stresses in the surface of the part.


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## ErichKeane (Dec 9, 2022)

Y'all got me off on a side project 

I'd ordered this and it came 2 days later. It is a decent "should work well enough" tool, though is clearly going to need some projects to make it good later.

However, I have to work on a stand now. I have some scrap steel angle and plate around, plus a 140 a welder, so this will occupy a few shop days.


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## dkemppai (Dec 9, 2022)

ErichKeane said:


> I'd ordered this and it came 2 days later. It is a decent "should work well enough" tool,


Is this one of those chinese No3 arbor presses? If so, you'll have to let us know what you think of it!


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## Charles scozzari (Dec 9, 2022)

ErichKeane said:


> Oh, no, I'm joking.  You were right, an arbor press is a better idea.  Just the (self-embraced) 'reputation' of this forum is "The solution to all problems is to buy more tools!" that I was teasing you for   I feel like we are the world's worst support group


I would like to put this out there and maybe it may give others an idea as option. I have a lower bench that makes using this much easier. It brings the tool lower so its at a more comfortable working 
	

		
			
		

		
	








	

		
			
		

		
	
height. All the guides are delrin as is the broach holder which is slotted for adjustments as needed. I used a 1" Acme rod as the pusher and when the broaching is complete the broach passes into a canvas bag below. It has a socket welded on top that I use to run the acme rod in and out.


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## WobblyHand (Dec 9, 2022)

I have that arbor press.  It works.  There's nothing elegant about it however, it is essentially the minimal "thing" that is a 3T arbor press.  I replaced the hand wheel on mine because it had razor sharp edges and flash on it.  The hand wheel wasn't worth fixing up, in my opinion.  Once the hand wheel and handle were replaced it was a lot better.  I also installed a small steel plate inside it so the screws were not directly bearing on the ram.


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## WobblyHand (Dec 9, 2022)

Charles scozzari said:


> I would like to put this out there and maybe it may give others an idea as option. I have a lower bench that makes using this much easier. It brings the tool lower so its at a more comfortable working
> 
> 
> 
> ...


That's very nice!  I like it.


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## ErichKeane (Dec 9, 2022)

dkemppai said:


> Is this one of those chinese No3 arbor presses? If so, you'll have to let us know what you think of it!


Yep! I got it from vevor com, as I was ordering something else as well.

So far: it's rough but probably works. The plate at the bottom is raw cast in the cutouts, so I probably am going to spend time with a die grinder on that.  The hand wheel casting is sharp as well, so I need to spend time with th grinder on it.

The ram itself is a little gritty, so I expect I'll spend some time cleaning, filing, and greasing that.

There is also some sort of alignment issues with the ratchet mechanism that likely needs some attention.

In all, its a casting kit that needs some finishing, and some of the raw stock is already to size 

I feel like I got what I paid for, at 1/5 the price of a "nice" import.

Even non ratcheting used ones around here are $600, so less than half price of those, so I still feel like I got a good deal.


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## WobblyHand (Dec 9, 2022)

ErichKeane said:


> Yep! I got it from vevor com, as I was ordering something else as well.
> 
> So far: it's rough but probably works. The plate at the bottom is raw cast in the cutouts, so I probably am going to spend time with a die grinder on that.  The hand wheel casting is sharp as well, so I need to spend time with th grinder on it.
> 
> ...


Pretty much my feelings on this arbor press.  A casting kit that needs a bit of attention to be ok.  The ratchet feature is very nice.  Hand wheel is awful, I replaced mine.  Much better now.


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## ErichKeane (Dec 9, 2022)

Alright, two bits of news! First, the plastic fears showed up! I was really excited to see that! They beat me being able to use them yet, but I'm glad to see they will be here when I need them!




Second, one of the challenges to the design is that it is built around a NMTB 20 tool holder, which basically doesn't exist. I like the advantage of using it instead of MT2, so I am going to have to make 2+ holders plus both spindles. However, I went to a tool dealer today who sells a bunch of "junk" out of a old warehouse. On a shelf off to the side, I found these;





These are two size-20 tool holders! They aren't the right thing to use as tool holders at all, and they don't have consistent drive tabs or draw bar. However, they will allow me to use them as a "go" gauge when making the spindles!


----------



## rwm (Dec 10, 2022)

Just wondering if you should consider a different spindle taper? How about an MT2 with a drawbar?


----------



## ErichKeane (Dec 10, 2022)

rwm said:


> Just wondering if you should consider a different spindle taper? How about an MT2 with a drawbar?


I ALSO considered the MT2, but my experience with Morse Taper is it getting stuck a lot.

The guy who drew the plans had the same concern, particularly with hammering on the back of the spindle, on what is a somewhat fragile machine.  The original prototype used MT2 FWIW.

I'm still considering it anyway.  It would be nice to just buy toolholders off teh shelf and just machine the ends I need on them.


----------



## rwm (Dec 10, 2022)

Good point. I was not thinking about removing the MT2! I assume the spindle is too small for a BT30.


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## ErichKeane (Dec 10, 2022)

rwm said:


> Good point. I was not thinking about removing the MT2! I assume the spindle is too small for a BT30.


Yep, exactly.  Thats why he chose the 20-size when designing, but no one makes/uses them for anything it seems.  And the two I've got are modifications on it for some sort of (DIfferent!) quick-connect in both cases I think.


----------



## rwm (Dec 10, 2022)

Those 2 will get you started and then you can make your own as you go. You could derust those in a small electrolytic bath pretty easily. I am always impressed how well that works.


----------



## f350ca (Dec 10, 2022)

I use MT2 collets in my indexing head. You don't need to draw them in very tight to hold, the whole point of the MT. They tap out / release relatively easy if you don't over do it drawing them in.

Greg


----------



## ErichKeane (Dec 12, 2022)

Whew... Did a bunch of work the last few days with sub par tools making an arbor press stand.

The grinder and paint makes me the welder I ain't, but nothing can save me from the painter I is 

It's at least as good quality as the arbor press I'm putting on it, so I'm happy enough.


----------



## ErichKeane (Dec 12, 2022)

And done! I even used it today to do my last collar.

However, I noticed that broaching made the threads fit pretty tight  I might have to use some lapping paste on these some day.


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## ErichKeane (Dec 14, 2022)

I think I've convinced myself that I should just do MT2.  I ordered some cheap stub blanks and a set of MT2 reamers.  I think that ends up making it more likely I'll get more blanks for future sizes 

I think it also makes the 'hard part' of making these parts on the lathe a non-issue.  Now I just have to figure out work-holding for the arbors in the lathe   I have a Jarno taper headstock, and no MT2 tool holder, so I might end up having to just make an aluminum 'arbor' for turning them (wasting a sizable hunk sadly :/), and hope the taper holds well enough to do the turning.


----------



## ErichKeane (Dec 16, 2022)

Spent the day in the shop, though only some on the hobber.

I wanted to get the lead screws extensions done first. I'd previously loctite attached them to the lead screws:



First step was to face them to length, then put in a center. HERE is where I messed up one, I made them all the same, despite having changed 1 of the 3 to have a slightly different design 




Next, I profiled them and finished the lathe work on 2 of the 3. The 3rd I did, but left it too short :/




I had 2 shoulders to do, plus a small threaded section



One mod I made was to put the threads on the end for a bit, since I didn't trust the set screw in the 3 ball handle to keep tension;
	

		
			
		

		
	




Next, I milled a key onto each with the mill and am angle plate.

I also needed to mill a key onto the bushings for each of these. I made an arbor to hold them in the mill, set it up, and milled all3!


----------



## ErichKeane (Dec 20, 2022)

Alright, so I did a lot of time consuming work today, trying to make the dials.  There was A LOT of failing today :/

I turned the blanks without taking pictures, then worked on the lines.

First, I tried out the dremel engraving tool by marking on the brackets:



Then, I set them up to engrave the dials.  This was REALLY time consuming, 100 lines each:




HOWEVER, I managed to screw up both of them.  The grizzly dividing head didn't do the 100 divisions correctly somehow.  I ended up on both of them having my last lines close enough to 'merge', perhaps 1/2 a line off.   I probably have to spend some time making these over at one point, but at the moment, they are good enough.

After that, I decided to clean up all my castings (the paint stripper rusted a bunch of it, so there was a lot of cleanup!), then assemble them:





ONE thing I noticed is the "L" bracket and the hobber quadrant don't line up.  I think I'm going to have to oval out the holes another 1/2" or so to make it alignable.  Unfortunately, this is one of the parts I can't for the life of me get the workholding right on the bridgeport, so I cut it the first time with a hand drill.  I wish I had a horizontal mill or right hand milling attachment, but can't find one reasonably priced :/




Otherwise, I think tomorrow I can start working on one of the spindles!


----------



## mattthemuppet2 (Dec 21, 2022)

lovely looking work Erich..

Speaking of right angled heads, PM on the way


----------



## ErichKeane (Dec 21, 2022)

I spent a bunch of today in the shop today as well!  BUT much of it was spent organizing my tap drawer and trying to level my lathe.  I think I did a decent job of it, but we'll see!

I wanted to get my hobb spindle housing done today, but realized it would be easier if I'd made the 'bearing retaining ring' instead.

I had a hunk of aluminum stock that seemed to be the only piece of material big enough in my scrap bin.  

I started by facing both sides, then cutting the OD.



Next, I cut the outside dimensions and inner dimensions (with a boring bar).  Only the length of the outer step, plus the diameter of it are in any way meaningful, the ID's tolerance is basically .100!





Before parting it off, I popped it onto the mill, and centered with a coax-indicator:



(PS, I discovered I have a spare coax-indicator if anyone is interested in it!  It has a cracked crystal, but is otherwise in perfect shape).

After dealing with a "Memory Overflow" issue in my DRO, I was able to use the bolt pattern tool to drill all the holes:




Then, a quick part off:




Followed by facing it off:




AND we're done!  here it is in place:




I made sure there was a ~5 thou gap when tightened down, so it is holding the bearings in place.




I ended up doing a bunch of adventure, including a trip to the Ford service department that took out 1/2 my day, but still ended up getting this started:




That is a 2" diameter, 12" long hunk of 1144 that will someday be the hobber spindle housing.  I've decided to just do MT2 like we all suggested, but I have a TON of material to hog out first.  It was a bit slow going, so I ended with only the largest diameter turned, and about 1/2 way down to the 2nd diameter.  A few stops were required to re-grind my tool as I got too greedy with my F&S


----------



## ErichKeane (Dec 26, 2022)

I spent another long day on the hobber spindle. I ended up getting a bunch of chatter with my roughing tool, but it cleaned up nicely with my pointed tool. This was a LONG day of material removal, mixed with lots of grinding HSS as I kept deciding that the S&F app I have was too conservative, and had reality correct me 

When we left me last time, I had just the left most diameter. This was me in the process of roughing out as much as I could for the 2nd diameter, bearing surface, N05 bearing but, and center section. Not many are visible here yet, but they are coming.



After roughing, I got the bearing area done as a light press fit, plus single pointed the strange 0.969-32 thread.

However, I messed up on the threads in a way I hope won't burn me. I cut by depth to the top of the tolerance. As I pulled out my tool to do thread wires, I crashed my cutter and snapped it off.  

I found that the nut is quite tight (requires a wrench to tighten), but I decided to take the risk and run with it, rather than the risk of trying to pick the thread back up, particularly with a 32 tpi thread. Hopefully I'll survive 




At this point, I am doing final turning for where the gears come out of the back of the spindle. But, you can see the 2nd bearing seat next to the blued area for my N03 .664-32 thread. By this point my "roughing tool", which gives my best finish, is no longer chattering, so I get the 5/8" diameter done with it.




And here I'm drilling for the drawbar. I drilled 13/32 as deep as possible on this side. You can also see my N03 thread is done, which turned out just about perfect for the nut! Seeing as this is the more important one for being able to take this apart, I consider this a win 



Next, I flipped the shaft around in the 4 jaw (after parting off!), And faced the flange.



Next, I finish drilling through for the drawbar, then a clearance to start the MT2. I started with the roughing reamer, but it is slow going and tedious, so the dinner bell called me in  a few more tasks to finish this, but it feels like the end is in sight!


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## rwm (Dec 27, 2022)

It is really not that hard to pick a thread back up. I have messed up enough threads so I have some experience there...
You could also chase the threads with a file maybe?


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## ErichKeane (Dec 27, 2022)

rwm said:


> It is really not that hard to pick a thread back up. I have messed up enough threads so I have some experience there...
> You could also chase the threads with a file maybe?


I've only done it a handful of times with varying success, and never with something as tiny as 32 tpi!

So it ended up being a bit of a risk either way.  I'm hopeful that it's good enough to get the nut threaded as far as it needs, though it might well take a bit of effort.


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## ErichKeane (Dec 27, 2022)

Also looks like McMaster has a .969-32 die for sale ($75, not as bad as I would have feared!), So that can be plan B.


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## brino (Dec 27, 2022)

ErichKeane said:


> Also looks like McMaster has a .969-32 die for sale



0.969"-32 TPI, what?

Well there it is under  American National Special (Unified Special) or "UNS"......
http://www.whittet-higgins.com/thrddim.php?id=1

I learned something today.... I can official shut off my brain!
Thanks Erich!

Brian


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## ErichKeane (Dec 27, 2022)

brino said:


> 0.969"-32 PTI, what?
> 
> Well there it is under  American National Special (Unified Special) or "UNS"......
> http://www.whittet-higgins.com/thrddim.php?id=1
> ...


Yup! Two new threads for me this time  N03 and N05 are "bearing retaining nuts" that all seem to have about 32 TPI that seems designed to match certain bearing sizes.


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## ErichKeane (Dec 28, 2022)

Alright, finished the hob arbor, and discovered a BIG mistake... I gotta think about it for a bit.

First, I finished up on the outside dimensions of the shaft, BUT I turned down the drive flange, since I'm not using it anymore. This means the bearing retaining ring doesn't need to be between the flange and bearings.



Here it is, all the turning here is done, and here is how the tool holder fits. I might need to ream it a little deeper, but I'm happy with it for now.






Next, I went to the mill to cut a keyway for where the gears go.
	

		
			
		

		
	




I had to turn down the larger bearing nut here, so I made a mandrel with a 5/8" bolt to squish it:







And, here I pressed the top bearings in place:



And installed the nut. Note it is backwards. It has a rubber retaining portion in it that I couldn't get to start on the slightly too tight threads. This shouldn't be a problem, the shoulder is still athe right size, and it clamps it right.




I got the whole spindle assembled into the housing, but forgot to take a picture!

BUT, here is my mistake. I went to start the other spindle, and realized I reversed the bearings! The larger bronze bearing is supposed to be on the drive side, and the smaller, plus retaining nut(another N05!) goes on the back.

SO, I have two choices; either remake the casting (which requires buying a new one, and new bushings), OR redesign it to have the retaining nut on the front.  I'm leaning towards the latter, but I'm going to sleep on it.


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## ErichKeane (Dec 29, 2022)

I opted to just re-design/reverse the spindle instead of re-making everything.  In the end, I have a happy outcome, but another problem that I have to figure out...

First, I found a poorly ground piece of HSS in my drawer to use as a roughing tool. I had to take 2" of 1144 down to 1 inch on this side.




I then did the parts of the shaft that goes in the bushings, plus the threaded portion for the retaining nut, and cut an MT2 socket in the end, and drilled as far though as I could from this side:




And it fit!



Next, I flipped it around to cut the 5/8 side the gears ride on. Started with roughing, then forgot go take a pic 



Cut a keyway:
	

		
			
		

		
	




Next, I cut some flats so I can use a wrench. I meant to go for 1-7/16, but messed up on the depth of cut, and decided to just go for 1-1/4.




Next, I had to bore out a factory bought gear, which drives this shaft. I also cut a keyway. I think I need a set screw as well, but didn't cut one yet (and the plans don't say to have one!).




And here it is all in place:





And here is my problem: when the feed is all the way forward, the end of the MT2 blank doesn't hit the end-line of the cutter! I am going to have to create some sort of holder for the gears that puts them far enough forward, ive got a good two or three inches of travel, so I'd like to be able to cut 2-3 gears at once.

I think I might make the shaft that connects to the arbor stick out quite a bit, perhaps one that just indexes off the current one, unless I can find an MT2 machinable arbor with a 3+" machinable section.


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## ErichKeane (Jan 3, 2023)

I didn't really get any work done today other than adding set screws to the keyed gear:




The rest of my time was trying to plan next steps, and getting distracted by this thanks to @mattthemuppet2



It's going to lead to MORE side projects as the arbor support doesn't match the arbor or my mill, so theres a bit of mods to the arbor and support, but it was too good of a deal to skip!

BUT those are future projects fortunately, and won't block this one.


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## ErichKeane (Jan 4, 2023)

Just a small part today, but 6 of them . This is one of the two parts to the quadrant gear holders. There aren't any plans for how to make these, so they are my design. 

I started with some .750 bar, faced and turned the last bit for the gears down to 5/8. 




Next, drilled and reamed to 3/8 for the shaft that goes inside of it.



After parting, they get flipped, and faced to length:



And here they are after those two setups:



Next I just cut a keyway, since this one's job is to keep the two gears riding on it in sync:



And done!
	

		
			
		

		
	




I'm hopeful I can start on the other sides of this tomorrow!


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## ErichKeane (Saturday at 6:51 PM)

I spent the last few days working on the other half of the quadrant gear holders.

This has two parts to it, one side that holds the previous part in a rotating fit, and the other that bolts to the quadrant. It does not need to be concentric, which has some work holding advantages. As before, this is a my-design part that wasn't in the plans.

First, I turned down 1" stock to 3/8". There is a shoulder on it with a little raised ring to be a bearing surface. I made sure to match it to the length of the gear holder parts (though those are all within 2 thou of length, so are effectively interchangeable).




Next, I drilled and tapped for a 1/4-20 to hold this side together:



And here it is assembled: 






As before, I'm making 6 of these, so there was a lot of repetitive work.

After those were done, I flipped them and put them in a collet chuck to turn the side that goes into the quadrant.

The shaft is a little under .400 (spec on the quadrants was .375, but I went way over on 3 of the slots, and way under on 2, I'm likely going to use my die filer to just widen all to about .400), and about .400 long before the 3/8" area I will end up single point threading.




After single pointing them, I made some 13/16" flats for a wrench:




And here they are loosely assembled! An observant person would notice there are only 5! During the turning of the 2nd half, I had a crash which spun it around in the collet, ruining it. SO, I'm going to live with 5! I suspect I'll rarely use more than 4, but was making 6 as that is the most I can imagine ever using.



And here are a few pictures of it assembled with some gears:






And, a video of it spinning 
View attachment PXL_20230107_213451957.mp4


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## Ben17484 (Sunday at 4:34 AM)

I’m enjoying following your progress on this. Keep up the good work and keep posting 


Sent from my iPhone using Tapatalk


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## ErichKeane (Monday at 8:54 PM)

So the list of things to complete is pretty short now!  

1-I have to do the linkage from the hob spindle to the work spindle (which the above parts do the start of).
2- I have to make the work-holding and hob holding MT2 adapters.  There will be a challenge there, as I have to make the work holding spindle particularly long (thanks to not doing the CAT20 holder, I ended up not 'wasting' as much room)
3- Mounting the electric motor
4- Figuring out how to drive the motor.  It is a 12V 337W motor that I'd like to have with a variable power supply, but finding one is going to be a touch troublesome.

SO, lets continue on #1.  There are a pair of universal joints that move the power from the big "L" shaped piece to the work-spindle.  On one side, the arm holds the gear (at the L) and the other, transfers to the worm gear (which is the 20-1 reduction).

First, I wanted to get the Universal Joint "centers" done.  This was a bit of an arbitrary choice, but makes the assembling of them as I go along possible.

I started with a 1.5" piece of 12L14, turned the outside down a touch, and turned the inside to 1.125" long enough to make both of these:




After that, I drilled/tapped the set-screw holes holes at 90 degrees (4 of them!) that act as the pivots for the universal joint.:




I drilled all the way through at each side, and used a square to line up the opposite side for the cross drilling, I believe I'm pretty darn close to perfect.

Finally, I parted it off:




I repeated the drilling/tapping/parting to get a 2nd one out of it, then used the surface grinder to get them down to thickness.  I managed to not get a picture of that part   After some deburring, they are done, though THAT picture is missing too.

After that, I decided to start on the worm-gear side.  

I started by turning it down to be a fit into the bracket it is going to ride in:




And you can see how it goes through here:




The worm gear rides in the center of that, and there is a set screw on a 2nd collar that holds it all in place (perhaps tomorrow's task!).


After getting that end finished, I flipped it around and started forming the Universal joint side:
	

		
			
		

		
	




It looks a litlte weird, but what I did was turn and face it, then drilled it out with my largest drill bit, then went in with the 5/8" endmill in the tailstock to get it about the right size.  In retrospect thats perhaps not the perfect idea, but it was nice to get that much material removed.

The worm gear is held from rotating with a key, so I cut that next.  This poor 1/8" endmill has received a ton of abuse during this project, and managed at least 1 more, though I think it is getting dull (it wondered for the first time)!   Either way, the keyway turned out good enough, particularly given how tight the gear is on the shaft.




Next, I needed to form the 'fork' end.  This was mostly just trying stuff to see how it would work out (I didn't spend much time planning this part!).  First I did top-and-bottom with my 5/8" mill:




In retrospect, I probably could have increased stick out and done this with side milling, but I didn't think about it.  Additionally, I needed it in this orientation for the next step, which is to better square up the 'insides' of the fork:




I suspect this is to prevent the forks from hitting each other (indeed, it says to spend some time with some files to round things over to keep it running smoothly, so I figure I'll be doing that anyway).

Finally, I used a center drill to make a sizable intent on each side for the grub-screws from the hoop to hit, and use as the pivot points:




After a few minutes on the knock-off scotchbrite wheel, here it is, next to the parts it'll end up keeping together!


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## dkemppai (Monday at 10:40 PM)

So, a couple of summers ago I needed a lot of power at 12v. Of course everyone wants 12v supplies, but no one wants 24v supplies. But if you dig close, some 24v supplies have remote control inputs for voltage and current limit. If they're switching supplies, just set them 12v and off you go. 

In my case I ended up with three really nice old TDK 1500W 24v units for $50 ea. Had to replace a few fans, but otherwise fully functional. 

I'll keep my eyes out for any more similar units...

A good xantrex or Sorensen adjustable runs for close to a grand now. Things are getting crazy for some of that used stuff...


Dan

Sent from my moto z4 using Tapatalk


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## ErichKeane (Monday at 10:47 PM)

Cool! Whatever you find would be appreciated!  Otherwise I'm looking at a pretty sizable box for a transformer and speed controller in 1.  This is the motor I ended up with: https://www.vexrobotics.com/217-2000.html

I found a cheap one at a local electronics store, and I know they are plenty torquey.


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## dkemppai (Yesterday at 3:20 PM)

Copying this from the profile post I sent earlier...
https://www.ebay.com/itm/284766134232
Honestly, for the money, I'd have a hard time not trying the above supply ,and one of these:
https://www.ebay.com/itm/224716884063

I just ordered one of these big PWM units. I wanted to get a closer look at what they're doing in there. I do switching power for fun. Yeah, I know... 

Anyway, to run a 12V motor from a 24V supply, just don't turn it over 50%...  

If you're worried about motor transient voltages, put an LC filter on the output of the PWM Module. Then you'd pretty much get DC out of the controller. It wouldn't be closed loop DC, but for what you're doing it might just fine. 

Dan


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## ErichKeane (Yesterday at 3:45 PM)

I've been definitely looking at those speed controllers, plus a 12v power supply transformer.  It isnt' quite clear to me what the power supply unit you're linking adds for me, can you explain?


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## ErichKeane (Yesterday at 9:12 PM)

I did 1 part today, which is the ring that clamps the last fork into the housing/keeps everything in place.  First, I faced and drilled 1/2" so it would slide on the shaft, into the end of some 1" 12L14.  




Next, I put it into the mill, and drilled for 2 8-32 set screws, per the plans. I again didn't part/split it off so that I could more easily make these drilled holes.




Then, back on the lathe, I parted it off:




I finished it to length on the surface grinder, since I have a magnetic chuck.  I pretty much could have done this on the lathe or mill if I cared to, but this was easy enough:




I ALSO had to shorten the gear that I got to make room for this.  I considered using a smaller set screw, but I would have been down to a #2 or something silly like that, so I instead took ~150 thou off the gear in the lathe:



Here are all 3 in place:



I haven't assembled yet, since the gear is still a little tight on the shaft, and I haven't made a key.  I might end up pressing the gear in place.

Next, I started on the next fork in the train (or at least, one of the middle ones).  These use a sliding fit with a pin in the side to account for length changes.  First, I turned the OD, reamed the ID on the lathe, and formed the back of the fork a bit.  I once again left it on the same piece of stock to save me trouble later:





Next, I had to cut a 1/8" slot down the side.  A pin will be pressed into the inner piece, and slide down this as the length changes.  I COULD have done something boring like use an endmill. BUT @mattthemuppet2 hooked me up with a right angle attachment and large arbor (and an arbor support, but the arbor support doesnt fit my mill or the arbor... both are future projects).  SO, no arbor support means I wanted to keep it as close to the head as possible.

I used a 3/32" cutter to rough out the slot:




I then used my 1/8" endmill to clean it up, and widen the hole a bit to make sure a .125 gauge pin slid nicely (AND, all the way to the end!).




I didn't get a chance to go further, a package showed up that I opted to unpack!


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## dkemppai (Today at 10:01 AM)

ErichKeane said:


> I've been definitely looking at those speed controllers, plus a 12v power supply transformer.  It isnt' quite clear to me what the power supply unit you're linking adds for me, can you explain?


With speed controller you should be able to run the 12V motor from 24V. The PWM reduces the average voltage, at 50% PWM output, the output is 12V average. The motor shouldn't care if that average comes from 100% from 12V, or 50% from 24V. (You probably wouldn't want 10% from 120VDC tho, for example).

The only point about the supply is, that is most bang for the $$$ you'll probably get right now. I think those are around $1000 new, and the guy claims these are tested. You should be able to get that motor spinning with variable speed for under $75. That's pretty affordable...
It's the path I'd take if I needed to spin that motor.   

Of course, this advise is worth exactly what you're paying for it...    LOL!


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## ErichKeane (Today at 8:20 PM)

So I did a bit more work on the workpiece side, did an Ace run for parts, and did a little bit of fitting/assembly.

First, I finished up the piece from last time, the 'outer' sliding part.  It started by forming the end on the lathe again like last time:




Then, using the mill to shape it and hit the divots for the set screws.  I spent a little extra time with the ball nose endmill on this side to blend the bar and the fork, since the bar is a greater diameter on this one:




Next, I started on the part that slides inside of this one.  It has a pair of pins to ride inside that slot, plus is a sliding fit inside.  First was a quick turn down to 3/8":




AND a test slide:




Before parting, I took it over to the mill to drill 2 1/8" holes for the pins.  They aren't through holes, so I drilled them with a 1/8" bit figuring I was loctiting them in place anyway.  I don't have a 1/8" reamer anyway, so this is as good as I was going to get   In retrospect, if I'd picked the pins up ahead of time, I could have tried an undersized drill bit and tried to fit it a bit better (or pressed it in!), since they turned out a touch loose:




And here are the two finished pieces, plus the one that was already finished:




However, before I can start getting all that together, I figured I'd start assembling the work side.  I assembled it first, though the shaft to gear is pretty tight.  It wasn't a big deal, but meant assembling required a press, and disassembling a punch:




Upon assembly, I noticed the gears didn't mesh very well.  First, because the flange on the bottom was hitting the bushing surround.  This is my fault since I reversed the bushings I think, but a bit of time with the boring head in the mill cleaned that problem up:





HOWEVER, a second attempt showed that the mesh still wasn't good, it was hitting the edge of those stops already before meshing.  I ended up putting the U shaped piece on the mill and taking 100 thou off:





AND here it is assembled. The gears seem to mesh pretty well, and it is stopped on the 'gears' instead of the metal when fully meshed, so presumably that means i don't have any more material to remove:




AND that is it for now!  3 more pieces left to do on this linkage I think, then I can start on the other parts of my list!


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