# Tool Post Grinder -Making a new one...



## Ray C

I've decided to re-make my tool post grinder.  The one I had was also home made but the bearings were a special design and the housing was too big.  Today, I drew-up the plans for a new one using commercial bearings.  The front bearing is a high precision Nachi-Fujikosi that was NIB that I picked-up for $50 (normally about $250).  It's a roller/taper type that can handle radial and axial loads.  The rear bearings are a standard needle-nose thrust and a needle-nose radial.  The PDF should show the whole picture pretty clearly but, I did not include the wavy pressure spring that keeps the shaft and taper bearing under load.  This thing will be sealed and filled 1/2 way with ATF.  BTW, does anyone know of a source for 1/2" diameter grease or oil rings?  Right now, the diagram shows O-ring grooves but, I sure would like to use seals instead.

I'll start building this thing soon but, can't do some of it because the thrust and radial bearing haven't arrived.


Ray

PS:  Click the PDF file and you can rotate the image in 3 dimensions.

View attachment TPGAssembly.pdf


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## xalky

Kaman bearing should have the oil seals. https://ec.kamandirect.com/us/index.jsp


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## Tony Wells

Look for a CR (Chicago Rawhide I believe) distributor. If they don't have the seals you want, they probably don't exist.


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## John Hasler

Ray C said:


> I've decided to re-make my tool post grinder.  The one I had was also home made but the bearings were a special design and the housing was too big.  Today, I drew-up the plans for a new one using commercial bearings.  The front bearing is a high precision Nachi-Fujikosi that was NIB that I picked-up for $50 (normally about $250).  It's a roller/taper type that can handle radial and axial loads.  The rear bearings are a standard needle-nose thrust and a needle-nose radial.  The PDF should show the whole picture pretty clearly but, I did not include the wavy pressure spring that keeps the shaft and taper bearing under load.  This thing will be sealed and filled 1/2 way with ATF.  BTW, does anyone know of a source for 1/2" diameter grease or oil rings?  Right now, the diagram shows O-ring grooves but, I sure would like to use seals instead.  I'll start building this thing soon but, can't do some of it because the thrust and radial bearing haven't arrived.


  Why ATF (and which one?)  I would have used transhydraulic oil.


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## Ray C

John Hasler said:


> Why ATF (and which one?)  I would have used transhydraulic oil.



ATF...  For the most part, it's just a lightweight hydraulic oil (about 7 to 10 W) dyed red.  In modern transmissions, it makes a big difference of course but, for chrome steel bearings, nothing fancy is needed.  I have countless gallons of hydraulic oil in storage but, it's all too heavy for a 1/3HP motor.

Anyhow, I think I have some fresh Dexron type from the last time I bought a bunch for heat treating.  According to the CAD calculations, this will only need 1/2 ounce.

Marcel and Tony:  Thanks for the tips... I'll see if I can locate those seals.  I looked for about 30 minutes and couldn't find a place that sold 1/2" ID.

EDIT:  BTW, the bearings are rated for insanely fast speed (upward of 15k RPM) but I'm only planning to let this thing top-out at 5k RPM.  The motor is a 1/3 HP 3 phase that I drive with a VFD.

Ray


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## Ray C

Someone asked for a better view so, here it is.  The wavy pressure washer will go to the right of the green thrust bearing.  The thrust bearing is shown as a monolithic piece when in reality, it's 3 pieces (2 disks sandwiching a plate with rollers).  The purpose of the pressure washer is to constantly apply force against the thrust bearing and in-turn, the shaft which in turn presses the taper cone into the taper race.  I want the pressure to be upward of 150-200 lbs.  The thrust bearing can take 5000lbs (dynamic) and taper bearing can handle an insanely high force.

The taper bearing race fit will be 1 tenth interference (i.e. sweated in). The needle radial will be a zero tolerance fit.


Ray

View attachment TPG-Exp-Assembly.pdf


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## Ray C

Ok, here's some action shots...  This is the front cap that holds the taper bearing.

This metal is 1045 that I fully annealed then, heat treated so the inside of the stock should be about 35 RC.  That should be plenty hard for this application.  Normally, folks will anneal then machine then, heat treat then, re-machine to size.  In this case, 35 RC is not hard to work with so, I'll just work with slightly hardened metal.  I actually prefer that as it cuts nicer.

The bore diameter for the bearing race is cut 1/2 thou under size of the race (which happens to be 1.571").  In the last pic, you can see it's a nice fit.  The rounded edge of the bearing fits in then it stops.  If I warm the cap to about 200F and cool the race in the freezer, it will drop right in.

The through holes were done on the mill using the DRO to put them 72[SUP]o[/SUP] apart for a standard 5 bolt pattern.

Enjoy...









Ray


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## Tony Wells

Ray, you using a LH tool to cut RH, or did you feed out....or are you using this to face?

Looking good so far!


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## Ray C

It was a side cut going from right to left but every now and then, I'll use a LH tool and reposition the QCTP so the engagement angle is still correct.  Often times I'll do this depending on what inserts are loaded-up.  In this case, to get that finish, I wanted a wider radius and that was the most convenient bit at the time.  -Yes, I know, there are dangers in doing this...

I used a naked carbide RH tool to get most of the meat off and it was on it's last leg when I started.  I used it until T minus 70 thou, switched over to that fresh bit, took a first cut, gauged it out and lined-up for the kill.  Missed the mark on the OD by a thou but, it's far from critical.

BTW, I'm loving these new boring bars I picked-up not long ago.  I'll show a pic.  Flat insert with no breaker.  Man, they work great.

Ray





Tony Wells said:


> Ray, you using a LH tool to cut RH, or did you feed out....or are you using this to face?
> 
> Looking good so far!


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## Tony Wells

Just a thought, but have you considered putting a couple of holes through for bearing race removal?


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## Ray C

Actually... I been thinking about that a lot.  If you look in there, I put a shoulder step in there to prevent the race from seating completely flat at the face.  My initial thought was that a small gear puller mechanism could be used to pull it out.  In hindsight, I've never seen a puller that small and would probably need to make something.  -So only then, after I got a chance to lay eyes on it, did I start thinking about a couple screw holes.

I'm thinking screw holes would make life a lot easier but, I haven't researched the oil seals yet and don't know if they'll be large enough to cover-up the screw holes.

---Still thinking about this one...  And I might just make a special tool to remove the race....


Ray



Tony Wells said:


> Just a thought, but have you considered putting a couple of holes through for bearing race removal?


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## f350ca

Nice design and workmanship Ray. On the oil seals, in such a dirty environment, (grit from grinding) would a felt wiper be better? If grit gets under the felt it tends to impact into the felt where it won't score the shaft.

Greg


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## DAN_IN_MN

How about 3 tapped holes that you could thread bolts into to press the race out?


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## Ray C

Here's the body piece, 1" wide.  For an oil seal between the main pieces, I'll make a circular groove at the same radius on each mating surface then, I'll fill it with some permatex.

As for oil seals...  If you look at the front piece, I made a groove for an O-ring and I'm still looking around for some proper oil seals.  -Just haven't gotten around to it.

Indeed, I could put some holes in there to assist removing the race but, I'm leaning toward making a special puller.  I made a step in there so the race won't seat totally flush and leaves room for the lip of a puller.  We'll see...

Also, yes, I left room between the shaft and the opening in the housing to put a felt ring in there.

Finally, I'll have to work on the safety shield next.  -Can't work on the 3rd piece of the body because the rear bearings have not arrived and I'm not cutting metal until they're in-hand and specd-out.




Ray


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## Tony Wells

You could mill out a pair (or three, depending on your puller) relief arcs that would allow a deeper engagement of the puller jaws.


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## Ray C

Tony Wells said:


> You could mill out a pair (or three, depending on your puller) relief arcs that would allow a deeper engagement of the puller jaws.




Wooo, now that's a good idea!  I like that...  I'll give it some good thought.  Thanks!


Now, for another matter...  Wish me luck on this.  I haven't TIG'd aluminum in a dog's age.  Just tried a couple similar practice pieces and it took a while just to get the settings pretty close.  -When will I remember to write these things down?  I want this to look nice so, I'll practice a good bit before taking the plunge.

Anyhow, don't laugh too hard but, I do not own a metal roller bender so I bent this by hand over a pipe.  It actually fits the circle pretty well.   I sure hope I don't screw this up...




Ray


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## ezduzit

Ray C said:


> ... The PDF should show the whole picture pretty clearly but, I did not include the wavy pressure spring that keeps the shaft and taper bearing under load...



PDF?

Don't you need that spring pressure to take-up the bearings' radial clearance?


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## Ray C

Yes, it will be needed and it will be included.  I didn't feel like spending the time to model the wavy-washer in CAD -and I couldn't find one in the parts library so, it wasn't included in the diagram (which I posted here as a PDF).

Ray




ezduzit said:


> PDF?
> 
> Don't you need that spring pressure to take-up the bearings' radial clearance?


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## Ray C

OK, now it'll work...  Even with one seriously funny looking wavy washer.

View attachment TPGWWWAssembly.pdf


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## Bill Gruby

Sorry Ray, been busy with the Tool and Cutter Grinder, I missed the start of this. Looking good so far. When I open the files all I get is a white page with the title at the top?? Any ideas ??

 "Billy G"


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## Ray C

Hmmm, let me see if I can post a JPG.  The files I'm posting are 3D PDF format and maybe your computer doesn't like it.  Stand by...

Ray




Bill Gruby said:


> Sorry Ray, been busy with the Tool and Cutter Grinder, I missed the start of this. Looking good so far. When I open the files all I get is a white page with the title at the top?? Any ideas ??
> 
> "Billy G"



- - - Updated - - -

Try this, Bill.  It's just a picture file.





Ray




Bill Gruby said:


> Sorry Ray, been busy with the Tool and Cutter Grinder, I missed the start of this. Looking good so far. When I open the files all I get is a white page with the title at the top?? Any ideas ??
> 
> "Billy G"


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## ezduzit

Ray C said:


> ...This thing will be sealed and filled 1/2 way with ATF.  BTW, does anyone know of a source for 1/2" diameter grease or oil rings?...



Perhaps this is the way things are normally done. Is there any concern about cavitation causing blown seals? Maybe try McMaster-Carr for lip seals. http://www.mcmaster.com/#ring-seals/=pxxf8y


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## Bill Gruby

Thank you Ray. I see that one. I never had trouble with any type PDF before?

 "Billy G"


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## Ray C

Oh yes, it's a concern...  I finally did get around to finding some grease/oil seals just like the ones you pointed to.  A dealer on Amazon is where I'll probably get them but haven't selected the precise ones yet.  Anyhow, as temperature changes, it will expand the fluids and/or slight pressure will build up...  If needed, I could put a small vent in there.

Do realize folks, I designed this thing "off the top of my head".  The front main bearing is probably way too big for the application but, it's what I happen to have on-hand because I picked up a precision bearing on eBay for cheap -so I'll use it.  I should also spend a few more moments calculating the correct pressure to be generated by the wavy-washer.  -Needs enough pressure to keep the taper bearing seated and not too much pressure to be a burden.  It may take a little trial and error....  The bearings are capable of WAY more RPM and force than this application calls for but as mentioned, this whole thing is made from shop drops (with the exception of the rear bearings which cost a whopping 20 bucks).

Hang in there with me on this project...  BTW:  I have a good bit of time off these days so, I should make steady progress building it.  -Still waiting for the rear bearings though and I can't finalize the drawings until they arrive.

Ray





ezduzit said:


> Perhaps this is the way things are normally done. Is there any concern about cavitation causing blown seals? Maybe try McMaster-Carr for lip seals. http://www.mcmaster.com/#ring-seals/=pxxf8y


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## Ray C

Oh boy, almost ashamed to show these.  It was a bit of a white-knuckle ride.  If you look closely, you can see the personality of about 6 different amateur welders -which is about how many times I had to start n stop this thing to make it all the way around.  If anything, the weld is sunk well and is very solid.  This is 6061 plate aluminum, 1/10" thick.  I was running about 65 Amps and could only go about 1.5 inches because it heats up so fast.  There's only a couple small voids which I won't bother to chase after.

Goes to show... "use it or lose it".  Last year when I was doing a lot of AL TIG, this would have been a snap and looked much better.

EDIT:  BTW, that piece of scrap clamped to the lip is not a part of this.  It was just a heat sink at the very end of the round band.  -Necessary to prevent the last 1" from melting before your eyes...






At least there were no burn-thru's or bottom-side bellies.  On the up-side though, it looks good after a quick sandblasting.  All ready for some paint (to obfuscate the bad welding).

I'll mark-out the cut-aways, put it in the mill and be done with this piece soon.




Ray


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## Tony Wells

I have a cast guard from a Dumore if I build a grinder. It appears to be a little smaller than yours, but no welding required. Yours looks fine. I probably would have just fused it on the outside and put a nice fillet inside. That way I could put a radius on the outside edge and not hurt the strength, and no one would see my ugly weld.

Or if I were just lazy, I'd machine it out of solid.


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## Bill Gruby

That would have been a lead pipe cinch out of a billet. Tough getting a good bead on thin material. Good job though.

 "Billy G"


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## Ray C

@Tony:  This plate a little large because of the way I intend to affix the front safety plate.  You'll see that soon enough.  Anyhow, I'm only planning to use 4" wheels on this but, it will accommodate a 5" (in case I ever need to grind a very small diameter shaft).

@Bill:  Aluminum is just plain finicky -especially thin.  I was really dreading the torch work on this because I knew I was out of practice.  I thought of making it from steel because it's a million times easier to weld.  Problem was that all the sheet pieces laying around are too big and didn't want to chop it up just for a 6" square piece....


....  I know that Santa exists so, maybe I wasn't a good boy this year and got passed up.  The bearings have not arrived for this project so there will be no Tool Post Grinder under the Christmas tree this year...


Ray


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## Ray C

Ok, after some thought and a suggestion from Tony, here's how we'll address the removing the bearing race.  We'll carve a couple slots to facilitate a puller.  I'll probably need to make a special puller (some day) but, that won't be a difficult task.  This method was chosen since A)  the bearing will probably last a very long time and B) the other option of drilling thru-holes didn't appeal to me because, the holes would need to be very small diameter (about #8-32 screw) and be threaded all the way through -about 1/2".  Also, the thru hole would be very close to the edge of grease seal on the other side. 

Also, as per plan, I've included a small round groove on the face to either accommodate an O-ring gasket or (more likely) some liquid Permatex.

So, here's what it looks like now.





Ray


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## Ray C

We're getting close to home stretch.  The thrust and radial needle bearings arrived today.  All that's needed now are the wave spring washers and oil seals.  Hopefully they'll arrive soon.

You might have noticed how the finish of the of cap faces are rainbow smooth toward the OD but get splotchy close to the center.  This is due to the SFM decreasing due to the constant decrease in effective diameter as it faces.  On these pieces, I use auto crossfeed and increase the machine RPMs with the VFD to keep it perfect as possible.  Since it's not a critical surface, I'm not too worried about it.  If you ever watch the high-end CNC machines, you can hear the motors revving like crazy as they get toward the center.  Some higher end manual lathes have a CSS (Constant Surface Speed) option to handle this.  

Some pics...

The thrust bearing just sits in there and doesn't require a tight fit.  I gave it 5 thou clearance around the OD.  There are two hard/smooth pressure washers that that come with the bearing set and they sandwich the needle bearings.  The wave spring washer will fit in the cavity and press against one of the washers.  This bearing is rated for 8,000 RPM and 4,000lb force.  That must be some seriously hard metal... -Not planning on coming anywhere close to those levels.  I'd love to see how they make those...




The radial bearing is also a slight interference fit.  In this case, I was shooting for 1/2 thou interference but it came to 4 tenths -still good enough to hold it in place.  The bearing has about the same rating as the other one.  The larger OD around the bearing is for the oil seal which is 0.25" wide and 0.999" diameter (weird size).  That cavity is 0.255" deep and 0.997" diameter.  I'll drill the 5 holes tomorrow.   The mill was tied-up with something else today.




... Until next time ...


Ray


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## dave2176

Ray,
I'm really enjoying this thread. All the great guys on the forum have got me adding to my to do list like crazy. Thanks for taking the time to share. 

Dave


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## Ray C

Thank you, Dave.  It's nice to hear -and I'm glad you're enjoying it.

It also goes to show that you don't need ultra fancy equipment to turn-out decent parts.  This is all done with modern production machines that didn't break the bank.  The lathe is a Precision Matthews 1236 that's a couple years old now and the mill is a PM-45 ...which is about 5 years old and I haven't had the need to tram it yet.  I use the machines a LOT but, the fundamentals are always cared for -and there's no sign of wear whatsoever...

One of these days, I'd like to show folks how to "sneak up" on a precision lathe cut.  I've taken my time on these parts (because I've got a long stretch of time off work) and all the dimensions within 2 tenths of where I wanted them -and all are within the tolerances I established.  It can be done and anyone can do it... but, you need to track previous cuts and watch the dials very, very closely.  Also need to watch temperatures and corresponding expansion coefficients.

The main shaft for this item is fairly complex and has 4 zones and 3 diameters and all but one are critical.  I'll make a point to show how to nail a diameter.  Heads up, it will be a long post...  hopefully I'll get to it tomorrow.

Ray






dave2176 said:


> Ray,
> I'm really enjoying this thread. All the great guys on the forum have got me adding to my to do list like crazy. Thanks for taking the time to share.
> 
> Dave


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## Bill Gruby

Which of these are you actually using Ray?

http://hubbardspring.com/subcategory.php/category/48/Spring Washers

 "Billy G"


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## Ray C

Looks like we'll get to the shaft early today.  The boss doesn't have anything planned for me today.

I'd swear I had some previously hardened shafts around but, no dice.  Right now, the shaft is in the oven.  It's 1045 material about 15/16" diameter that we'll heat treat to RC42.  According to the book, at this hardness level and diameter being under 1.25", it will harden all the way through uniformly if a water/brine quench is used (not so for oil quench).  RC42 is chosen because it's still easily cut with carbide.  Once you get beyond 45, I use ceramic inserts.

The shaft needs some hardness mainly because of the small section that rides in the radial roller bearing.  Soft metal would deform in fairly short order.  Also, hard metal cuts with a smoother finish (at the expense of requiring more cutting pressure).

Here's what it looks like -and unfortunately, the piece is a little more complicated that I'd prefer.  The extra diameters are driven by the bearing I happen to have on hand.  BTW, I'm treating two pieces of stock.  This piece has several critical dimensions.  So far, I've have good fortune and haven't blown any pieces yet -but now isn't the time to get cocky.  This is going to give me a run for my money because it's thin, will require slightly higher cutting pressures  -and I'm shooting for -0.0000, +0.0002" tolerances (translated: it's diameter cannot be under spec and is allowed to go over by 2 tenths).  If I get in a pinch, I will resort to using grinding compound to get the critical parts in spec.





OK, see you in a couple hours when the stock is done cooking.

Ray


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## Ray C

Hi Bill...  G'morning....


I settled on these.  Same ones you found...

http://www.amazon.com/gp/product/B0085ZO75G/ref=oh_details_o00_s01_i00?ie=UTF8&psc=1


BTW:  We're delayed a bit this morning...  Went to check the oven and it was going the wrong way (cooling down).  The heating element wire came loose.  -Lot's of expansion/contraction and a screw loosened up.  We're back and running now.



Ray





Bill Gruby said:


> Which of these are you actually using Ray?
> 
> http://hubbardspring.com/subcategory.php/category/48/Spring Washers
> 
> "Billy G"


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## Senna

Ray C said:


> Looks like we'll get to the shaft early today.  The boss doesn't have anything planned for me today.
> 
> I'd swear I had some previously hardened shafts around but, no dice.  Right now, the shaft is in the oven.  It's 1045 material about 15/16" diameter that we'll heat treat to RC42.  According to the book, at this hardness level and diameter being under 1.25", it will harden all the way through uniformly if a water/brine quench is used (not so for oil quench).  RC42 is chosen because it's still easily cut with carbide.  Once you get beyond 45, I use ceramic inserts.
> 
> The shaft needs some hardness mainly because of the small section that rides in the radial roller bearing.  Soft metal would deform in fairly short order.  Also, hard metal cuts with a smoother finish (at the expense of requiring more cutting pressure).
> 
> Here's what it looks like -and unfortunately, the piece is a little more complicated that I'd prefer.  The extra diameters are driven by the bearing I happen to have on hand.  BTW, I'm treating two pieces of stock.  This piece has several critical dimensions.  So far, I've have good fortune and haven't blown any pieces yet -but now isn't the time to get cocky.  This is going to give me a run for my money because it's thin, will require slightly higher cutting pressures  -and I'm shooting for -0.0000, +0.0002" tolerances (translated: it's diameter cannot be under spec and is allowed to go over by 2 tenths).  If I get in a pinch, I will resort to using grinding compound to get the critical parts in spec.
> 
> 
> View attachment 66675
> 
> 
> OK, see you in a couple hours when the stock is done cooking.
> 
> Ray



That part would be an ideal candidate for a good cylindrical grinder. Turn everything .001-.002" large and then spin it between centers on the cylindrical.
It could also then be turned in the soft state, heat treated to the ideal hardness without regard to cutting suitability, and ground for size and finish.
I'm sure a machinist of your caliber will do fantastically, perfectly well on your lathe but a cylindrical grinder is a pretty neat tool to have.
You should be on the lookout for a good B&S 13 or Cincinnati #2 in the future. 
Super versatile machines and I believe you'd use the snot out of one if you had it.


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## Ray C

You're absolutely right!  I'm doing a compromise for a few reasons though.  Ideally, I'd turn it slightly oversize with some normalized soft metal then take it down with the TPG or better yet, a cylindrical grinder.  Being the kinda guy I am, I used the old TPG for parts as, it was way too big and heavy.  Also, even if I had a cylindrical grinder A) I'm completely out of room in the shop and B) I'd have to teach myself how to use it first .

Also, I'd prefer this piece to be about RC 50 but low 40's will have to do.  I've already thought of re-making the part the right way once I get this TPG in a functional state then, swap-out the original one.  We'll see how this goes...

Ray

BTW:  Hmmm, "machinist"... -not so sure about that title yet...





Senna said:


> That part would be an ideal candidate for a good cylindrical grinder. Turn everything .001-.002" large and then spin it between centers on the cylindrical.
> It could also then be turned in the soft state, heat treated to the ideal hardness without regard to cutting suitability, and ground for size and finish.
> I'm sure a machinist of your caliber will do fantastically, perfectly well on your lathe but a cylindrical grinder is a pretty neat tool to have.
> You should be on the lookout for a good B&S 13 or Cincinnati #2 in the future.
> Super versatile machines and I believe you'd use the snot out of one if you had it.


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## Senna

Ray C said:


> You're absolutely right!  I'm doing a compromise for a few reasons though.  Ideally, I'd turn it slightly oversize with some normalized soft metal then take it down with the TPG or better yet, a cylindrical grinder.  Being the kinda guy I am, I used the old TPG for parts as, it was way too big and heavy.  Also, even if I had a cylindrical grinder A) I'm completely out of room in the shop and B) I'd have to teach myself how to use it first .
> 
> Also, I'd prefer this piece to be about RC 50 but low 40's will have to do.  I've already thought of re-making the part the right way once I get this TPG in a functional state then, swap-out the original one.  We'll see how this goes...
> 
> Ray
> 
> *BTW:  Hmmm, "machinist"... -not so sure about that title yet*...



I'm completely convinced that title fits you. In fact, having seen some of your work, Master could precede that title.


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## Ray C

Here are the shafts still in the quench bath.  I wasn't worried about decarburizing so, they sat in the oven naked.  The scraps on the bottom prevent the hot pieces from melting thru the aluminum pan.  It started-out with 3 gallons of cool brine water and the parts went in at 1550F (soaked for 40 minutes) and cooled off in about 20 seconds.  The water temp is now 170F.  I'll let the parts sit in the warm water about 30 mins until the oven cools to the desired tempering temperature of 700F.   With a 1 hour tempering, followed by an open air cool-down, the parts should be about RC 42.

In their current hardened state, these parts should be approximately RC 55 -which is about as hard as 1045 can get.  Metal in the post-hardened condition is highly unstable, subject to easy fracture and is considered dangerous to machine.  If I threw them on the ground, they'd probably fracture.  Right now, they are basically "metal glass" and if tapped together, ring like a bell.  The tempering process is critical...




Ray

PS:  As predicted, the shop is nice and warm now .  Nothing better than heat treating on a cold day.


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## mattthemuppet2

Senna said:


> I'm completely convinced that title fits you. In fact, having seen some of your work, Master could precede that title.



I agree, although I think Craftsman is more suitable than Machinist. It's always a pleasure to watch and learn from Ray's project threads, even if I'm not always sure what's going on


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## Ray C

So, here's the metal.  I wanted to take a test cut and check the hardness and if you look in the center of the small surface ground piece in my fingers, you can see the impact divots from the Brinnell tester.  Mine has a round ball impacter on it right now.  And the results are RC 40 tested at the center and inside section of that cut .  If I test at the outside end of that cut piece (which is 1/2" long), its RC 43.  This is because the ends of the rod cool off faster during the quench.

Anyhow, the goal was 42 and we got 40...  Close enough to go puff on a cigar for a while...






... And one other thing...  I appreciate the kind words and sentiment but, the term "Machinist" should be reserved for those who supported themselves and made a livelihood doing it; nor, am I a Craftsman.  I don't have an artistic bone in my body.  In general,  "Advanced Hobbyist" is fitting and appropriate...  

Ray


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## mattthemuppet2

Ray C said:


> ... And one other thing...  I appreciate the kind words and sentiment but, the term "Machinist" should be reserved for those who supported themselves and made a livelihood doing it; nor, am I a Craftsman.  I don't have an artistic bone in my body.  In general,  "Advanced Hobbyist" is fitting and appropriate...
> 
> Ray



all right all right, Master Advanced Hobbyist it is then  Besides art and science are just two sides of the same coin, a perfectly turned piece is just as artful as a bucket of paint splashed on a canvas.


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## Ray C

Well, this was easy; took about an hour (because I'm in slow-motion mode these days) and the best part is that it only took one try. 


So here's how things go...

First, I have absolute faith in my 5C collet chuck and I know with great certainty my tailstock is dead on.  -These things are pre-conditions -always!  If you don't know and trust your machines, work at it until you do.

I started out by selecting the 15/16 collet sticking the shaft all the way in with just an inch sticking out.  -Face it, drill a center hole then, turn about 1/2" of the side down to 3/4" dia.  Flip the shaft around and do the other side.  Now, grab a 3/4" collet, insert one of the fresh ends, tighten things up and put the live center into position on the tail end.  None of this is shown in pictures BTW.


I'm using carbide so, this piece being under 1" and ultimately going down to 1/2" needs to spin between 1400 and 1800 RPMs.

First, I'm going to work from the inside out.   BTW:  Initially, I wanted the largest diameter in the center to be 1.1" dia but, the closest piece of stock was 15/16".  -No big deal because that large diameter only needs to be big enough to push against the thrust washer.

First, I take a pass about 10 thou DoC just to get the scale off.  Important:  Set your crossfeed dial to zero as a reference point and as you're doing this, never lose track of where the dial was set from the last cut.

The area I'm pointing to is where the taper bearing will be pressed onto.  It's critical dimension that needs to be 1 thou over the bearing ID.  The diameter needed here is between 0.6875 and 0.6885 (because the bearing ID is 0.6875).  I want a slight sweat interference fit.




Next, take three critical measurements (left, center, right) of the area you just cut.  If you have taper, now's the time to fix the tailstock.  And if you don't trust your chuck, spinning between centers is probably a better alternative.  In this case, the taper over that 3" segment was about 0.0001" -good enough!




My first measurement here was 0.8835".  Now, dial in exactly 10 thou and take another pass. I'm going to make successive passes at 10 thou because with metal this hard it's the lightest cut you can take and still get a good finish.  Deeper cuts will bend a shaft this long and thin.  Second measurement was 0.8645" so the difference is 19 thou.  Dial in 10 more, take a pass and measure.  Next one was 0.8450" for a difference of 19.5 thou.  This process continues and after several more cuts, it's clear that every time I dial in 10 thou, about 19.5 thou comes off the diameter.

With a starting diameter of .8835 and a final diameter of .6885, I'll need to make about 10 passes.  The trick is to carefully watch and adjust your settings so your last pass is taken at about 10 thou DoC.  You don't want to take your last pass at 15 thou DoC because that might bend the rod and not take off the 30 thou you were hoping for.

Also, sometimes you'll get intermediate readings like .7693.  The dial only has 1 thou graduations so, the next cut you take, split the numbers as best you can.

Heat:  I was running mist coolant for the whole job and I could tell the part was about 100 to 110F.  Even this slight amount will expand the piece very slightly.  Let's say your final cut need to have 19.5 come off.  Theoretically, you should dial in 9.75 thou more from your last cut.  In a case like this, the part will decrease about 0.0001 when it cools off to 68F.  I would make every attempt to read the dial and increase by 9.7 thou (you need to estimate between the lines).

As it turns out, on the last pass of this, the mic read 0.8683.  The part has now cooled to room temperature and it's reading exactly 0.8682.  I was hoping for 0.8685 so I'm 3 tenths shy but, still within spec of my desired -0.0000, +0.0010 tolerance from 0.8675.  




And here's what the finished piece looks like.  The 1/2" diameter area, now that it's room temperature is reading 0.5006 (within spec).  The intermediate diameter is 0.6252.  It was supposed to be 0.6250 (in spec).




And finally, Senna is right.  The proper way to do this is with a cylindrical grinder or a TPG -but you can get real close to perfect with a lathe.


Ray


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## ezduzit

Ray--thanks for sharing the reasoning and details of all this with us. Just curious if you had checked the bearing ID, yourself, prior to fabricating the shaft?


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## Ray C

Thanks...

Yes, absolutely I checked the bearing ID and OD.  The taper bearing was an expensive, precision bearing that was one of a matched set.  Picked it up for 50 bucks (normally 250 for the set).  The specs said 0.6875 and that's exactly what I read using a telescoping gauge at indoor room temperature.  It read about a tenth less in the garage where it's much cooler.

I didn't cut some of the body sections until the radial and thrust bearing arrived as I wanted to verify them before cutting metal.  They too were dead on as advertised.  I did however cut the cavities for the wave spring washers but, the tolerances there are loose as a goose.


BTW:  This metal shaft did indeed harden all the way through.  From the first cut to the last one, the machine never changed pitch as it does with uneven metal as you cut deeper.  In this case, every cut sounded and felt the same.  I don't think I'll need to re-make the shaft.  It's plenty hard and was sparking a good bit as hard metal tends to do.


Ray




ezduzit said:


> Ray--thanks for sharing the reasoning and details of all this with us. Just curious if you had checked the bearing ID, yourself, prior to fabricating the shaft?


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## Ray C

Just a little more work today...  Fun work -and the welding went a little better on the thicker aluminum.  Just a couple more pieces to make; namely, the bottom bracket and sheaves.  Still waiting on the wave spring washers and oil seals which are supposed to arrive around Jan 3.




Yep, you're thinking the same thing I thought...  -Looks kind'a like a toilet paper hanger  .  See, I told you; I don't have an artistic bone in my body.




Ray


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## Ray C

Still dilly-dallying along here, working on the bracket.  I didn't pre-design this part as it's my experience that when it comes to matters of "ergonomics" and basic positioning, setting-up prototypes is very productive.  In this case, I fiddled around with a few methods of making the bracket to find a solution that was simple and effective.  Here's what we have so far.  I'm re-using the base to the ball turner simply by drilling some holes in it.  It can still be used for the ball turner.  Also, you might be wondering why I'm using aluminum...  To be honest, I'm not all that crazy about AL but it happens to be very good at damping vibration and if thick enough, is pretty darn strong.

It attaches to the crossfeed like this:




Here it is with the components laid roughly in place.  BTW:  I bought the little HF grinder just for the motor to drive the TPG.  I'll remove the grinding wheels and covers and put a sheave on one side.   As for the TPG, depending if a 4 or 5" diameter wheel is installed, there's enough crossfeed travel to work on very small diameter shafts up to 5.5" diameter.  That should be more than adequate for my needs.  Anyhow, everything has clearance with the head and tailstock.  






Ray

PS:  I have no idea why this additional picture insists on being inserted in this post.  -Go figure...


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## Ray C

Slowly, the parts are arriving...  The thrust washers arrived today.  All that's missing now is one of the oil seals.  -Bummer... I ordered two seals from the same place at the same time and they shipped them separately. -Go figure.

Everything is fitting nicely so far.  By warming up the cap and cooling the bearing race, it fit in the recess with a few light taps with a brass rod.  Same story when fitting the shaft in the OD of the bearing.





So, here it is partially assembled and being tested for runout.  That's a Tenths TDI and it's rock solid.  The needle sits on one line and just twitches a bit...  Cool...




One little bit of bad news though... The little HF grinder that was purchased just to use the motor is totally inadequate and has no power whatsoever.  I'll return it.  By pressing my thumb on the smooth part of the shaft, I could lock-up the motor.

I have a 3 phase, 1/3 HP motor that I could use but, it's ultra-industrial duty and weighs WAY too much.  Seriously, the thing is about 45+ lbs and I just don't want that much weight sitting on my carriage and way nor do I want to heave it up there every time I use it.  -The search for a motor continues...

BTW:  The rest of the bottom bracket is all done but, I was in a hurry and didn't take pics.  -We'll catch it next time.


Ray


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## Senna

Ray, have you considered using a DC treadmill motor and control?

I'm thinking you could select pulleys to maximize torque and use the speed control to find the best rpm to give you the best results.

They aren't too heavy either.

Just a thought.


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## Ray C

All possibilities are on the table and I'm open to suggestions...  This time of year, everyone is making New Years resolutions to lose weight so, in a few months, all the unused treadmills will become available .

Good thought...  I don't plan to weld any of the motor brackets so, I can change things later as desired.


Ray






Senna said:


> Ray, have you considered using a DC treadmill motor and control?
> 
> I'm thinking you could select pulleys to maximize torque and use the speed control to find the best rpm to give you the best results.
> 
> They aren't too heavy either.
> 
> Just a thought.


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## xalky

Senna said:


> Ray, have you considered using a DC treadmill motor and control?
> 
> I'm thinking you could select pulleys to maximize torque and use the speed control to find the best rpm to give you the best results.
> 
> They aren't too heavy either.
> 
> Just a thought.


 I like that idea. How about a router motor with one of those cheap router motor speed controllers. I have a spare router motor here you can have Ray. You'll have to make a mount for it though.

Marcel


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## Ray C

Thanks and I appreciate the offer -and I might take you up on it...  I called a buddy who has a good junk collection and he's pretty sure he's got a few motors to choose from.  He lives a mile away so, we'll see what turns-up there.


Ray



xalky said:


> I like that idea. How about a router motor with one of those cheap router motor speed controllers. I have a spare router motor here you can have Ray. You'll have to make a mount for it though.
> 
> Marcel


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## Ray C

Some New Year's Eve eye-candy...

It's assembled but in these photos, some of the bolts were just finger tight so if anything doesn't look aligned, hold-off on letting me know until you see the final photos...

It will come apart one more time when I finally decide on how to attach the grinder wheels.  Am thinking of a simple thread on the shaft or possibly something a little fancier.






It isn't all that large as you can see.  The CAD program says the body weighs about 5lbs




Happy New Year...


Ray


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## ezduzit

Ray C said:


> ...thinking of a simple thread on the shaft...



Sounds right.


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## xalky

Nice Ray! What kind of grinding wheels are you gonna use, regular bench grinder wheels? Is there a shoulder on the shaft on the grind side?


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## Senna

Ray, it's probably more trouble than it's worth but have you considered tapering the shaft like a SG spindle and making small balancing adapters like you make for your SG?
I can see a few advantages to this approach but the work would be considerable.


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## ezduzit

How will you handle mounted stones?


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## Ray C

Yes, there's a shoulder on the shaft for an arbor plate.  You can see it in the PDF model.  It extends past the edge of the shield and nuts on that side of the unit.

I'll probably go with a simple threaded shaft.  I'll put a little square notch on the drive side so I can use a wrench to tighten the nut on the grind side just a tiny bit (not too much tension of course).  As for wheels, I have some 4 & 5" wheels in medium and fine grit that are high speed and meant for applications like this.  I'm hoping they well balance well and if not, I have some methods to address that.

@ezduzit:  You asked about mounted stones...  I'm not sure what you mean.

Anyhow, there will be a safety cover over the guard.  It's sitting on the work bench and is not done yet.

-Happy 2014...

Ray


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## Senna

ezduzit said:


> How will you handle mounted stones?



I hope I'm not out of place here but I don't think Ray designed this tool to spin at the RPM required for internal grinding with small wheels or mounted stones.
Even the old plain bearing ID grinders are designed to spin at least 10,000 RPM and the newer, high tech ones can spin to 100,000+.


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## Ray C

Ah, I got y'a...  Correct.  This was designed for external grinding.  The bearings are all rated for 10,000 RPM (or higher) but my plans are to keep this in the 6000 range.  I have another idea in mind for an internal bore grinder.  Still thinking about it...


Ray





Senna said:


> I hope I'm not out of place here but I don't think Ray designed this tool to spin at the RPM required for internal grinding with small wheels or mounted stones.
> Even the old plain bearing ID grinders are designed to spin at least 10,000 RPM and the newer, high tech ones can spin to 100,000+.


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## ezduzit

Yeah, that's what I meant by mounted stones...the die grinder style, for internal grinding.


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## DMS

A "mounted" stone is just a small abrasive stone fixed to a steel shank. As opposed to a type that fits to a small re-usable mandrel, and are usually sold separately from the mandrel.


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## Ray C

Well, it seems to be working... -but not without a lot of chasing around.  None of the motors my friend had were suitable.  After making shaft adapters and trying two of them, I bit the bullet and bought a large general-purpose 2 Pole (3600 RPM) 120/240  motor.  Since the 1/2, 1 and 1.5 HP units all weight about 18 lbs, what the heck, I bought the 1.5 HP unit because it was only 39 bucks more.  It was on sale at Harbor Freight and it runs surprisingly smooth and quiet.  It's a larger form factor than I wanted but the TPG does not get used all that often and, I might find other purposes for it later.

I had two wheels; a 4" 80 grit which I didn't have good luck with and a 5", 60 grit which did a nice job.  I just ran a quick test piece which was the left-over hardened shaft from earlier in the project.  I put a nice carbide cut on it, switched over to the TPG and gave it a shot.  It works quite well.  I followed-up with a buff and you can judge for yourself...

Pretty obvious... the motor is temporarily mounted because I just wanted a test run.  Overall, it runs very quite and you can hear the air coming off the wheel.  I still didn't receive one of the oil seals so, I make a temporary rubber gasket.  Surprisingly, it's not leaking.   I let it run for 30 minutes and the TPG housing just barely felt warm -maybe 10-15 degrees warmer than the lathe bed.

The picture right now shows a 1:1 sheave setup because the buffing wheel is only rated for 3600 RPM.    If I stick with this motor, I'll need to make a sliding motor bracket to accommodate different diameter sheaves.




And here's piece after a 1 pass buff.  It's pretty smooth.  Now for the bad news...  I was going to change back to the 5" #80 and in my frantic hurry to do so, I dropped it and chipped the edge -so it's in the garbage can where it belongs.   Oh well, I guess it was time to get another one anyhow.




Over the next couple days, I'll put a few finishing touches on it -and hopefully the grease seal will arrive so we can do the final assembly with the permatex gasket stuff between the body segments.  Right now, I just made gaskets out of thin paper -and oddly enough, it's not leaking...  -Go figure.

I'll check back in a couple days on this project when the oil seal arrives.  In the mean time, I'll install an oil drain plug and pretty-up the base a little.


Ray


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## ezduzit

Good work on getting it tested. But that motor just seems vastly disproportional to the job needing to be done.


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## Ray C

Thanks...

I hemmed and hawed about the motor....  Size wise, it doesn't look very appealing but, the motor weighs 19lbs which is as much as some of the treadmill and other DC motors I looked up.   There are no clearance problems or that would have shot it in the foot right away.   Anyhow, I weighed the whole setup and it's 33lbs which is about the same as a 1/2 HP Dumore TPG.  If I find a better motor, that will be great.  This one here will always find a purpose somewhere else if I find a better one. 

Ray





ezduzit said:


> Good work on getting it tested. But that motor just seems vastly disproportional to the job needing to be done.


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## xalky

Looks good Ray! As Tim the Toolman Taylor would say...it needs "more power".:thumbsup:  I have the 1 hp , 1725 rpm version of that motor running my southbend 9" lathe and it doesn't even groan a little bit. ) I just may have to build me one of these Ray. I've been looking around for a used Dumore TPG and the beat up ones are going for $500 or better. I got 2 motors sitting on the shelf over here. A 1/4hp 1725 rpm and a 1/3hp 1725 motor just waiting to be put to good use.  Getting the right bearings at the right price is gonna be the challenge.

Marcel


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## Ray C

The 1/3 HP would be desirable.  The taper bearing has a lot of force on it; as such, the shaft can be spun with your fingertips but, it's not freewheeling.  Also, the oil seal is a very tight fit.  Finally, with it filled 1/2 way, even with light oil, the motor will constantly be pushing against the viscosity of the oil.  -Moral of the story, 1/3 or 1/2 HP is the way to go.

You're right about the Dumore units...  $money$...   Ones in good shape are going near a grand.  I've got about 100 bucks invested in this.  10 for oil seals, 20 for the two rear bearings, 10 for the wave washers 10 for the thrust washer -and I think 25 for the front bearing (lucky eBay win) -and another 20-25 in miscellaneous stuff like permatex, threaded rod and a handful of nuts & bolts.   All the metal was shop-drops.  -Of course, the motor was 139 on sale so, I guess this thing really cost 239.  No doubt, I'll use the motor for other things here & there...

I've always wanted to pull a Dumore apart just to see what magic they have inside... Anyhow, I designed this thing with simplicity in mind and it was on the drawing board about 2 or 3 times before settling on this.  I came up with other designs but this one takes into account expansion of the shaft as it warms up.  The amount of space for the wave washer is critical.  Too much and the shaft will wobble... too little and it will seize the bearings when it expands to size -and yes, I actually calculated the amounts of expansion for 1045 steel.  All those cavity depths were important within a thou.

If I had to build another one, I'd only change one simple thing... Only use three holes/bolts instead of the five.    I thought about making the body a smaller diameter by threading the body sections (male and female) and screwing them together instead of using draw bolts.  -Too much work and didn't feel like messing with it -although it would have been cool to do it that way and I could have had further optimization of the side brackets that hold it to the base.  ... In a nutshell, I didn't want to do all that stuff not knowing if it was going to work or not.

I'm actually impressed with the HF motor.  No doubt, I'll get a double pole switch and wire it for 240.  It's 120 now.

Ray





xalky said:


> Looks good Ray! As Tim the Toolman Taylor would say...it needs "more power".:thumbsup:  I have the 1 hp , 1725 rpm version of that motor running my southbend 9" lathe and it doesn't even groan a little bit. ) I just may have to build me one of these Ray. I've been looking around for a used Dumore TPG and the beat up ones are going for $500 or better. I got 2 motors sitting on the shelf over here. A 1/4hp 1725 rpm and a 1/3hp 1725 motor just waiting to be put to good use.  Getting the right bearings at the right price is gonna be the challenge.
> 
> Marcel


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## Ray C

Had a little time to play with this again today after I chased around to find a 5" wheel. Here's piece freshly ground.  I took two passes; the first was about 1/4 thou and the last...  I barely blew on the dial from the previous pass.

The results are good.  This piece was just ground and not polished.  The iPhone camera doesn't do it justice.  When I look at it closely, it's so polished that my eyes can't focus on it




-Still waiting for the oil seal...  I want to hurry-up and put this project behind me.

Ray


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## xalky

Wow nice! What grit wheel are you using? What rate of feed on the long feed? Picking your brain to stash in mine!)


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## Ray C

Careful now... you might accidentally do a Vulcan mind meld and you'll find yourself howling at the moon and staying up all night trying to figure out how to remove 0.0001" of metal off a round shaft.

Feed... Slow!  The lathe was running at/around 300 RPM and the feed was set at the lowest speed which I think is 0.0015 IPR.  That ground section is about 3" long.  I didn't time it but, would guess it took 6-7 minutes to go the 3 inches.


The wheel is a 60 grit, 5" diameter AO only rated for (and run at) 3700 RPM.  I'd like to get a finer wheel just to see how that looks and I plan to get 6000+ rated wheels and run at/around 5000 to 5500 RPM.


Ray





xalky said:


> Wow nice! What grit wheel are you using? What rate of feed on the long feed? Picking your brain to stash in mine!)


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## xalky

I never would have guessed a 60 grit wheel would give such a nice finish, but I guess the fine feed makes up for the course wheel. I gotta start cutting back on my coffee consumption at night. Lately I've been rattling all kinds of projects around in my brain before I fall asleep. 

On another note, I just ordered the bearings for the Rotary Broach build. I'll be doing a how-to on it once the bearings come in.

Marcel


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## Ray C

Oh, BTW:  The wheel and shaft must rotate counter to each other.  -And make sure you cover your ways with paper towels sprayed with WD-40 etc.  Surfacing the wheel with a diamond makes a fair amount of grit/dust.  The dust from the actual grind is not bad but still, keep your ways covered with oily paper towels.  The oily towels seems to attract and retain the grit better.  I'd shy away from using regular cotton rags -lest one gets caught in the leadscrew or some other undesirable mechanical location.  A paper towel isn't going hurt anything if it gets jammed in a crevasse. 


Ray


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## xalky

This is most likely going to be my next project Ray. I just finished up the rotary broach. I've been wanting a TPG for a while. I'm looking forward to the 2D drawings. 

I already have the bearings here, thanks to you pointing me in the right direction on Ebay. I'm gonna study this thread and start rounding up materials for it. I'd like to find a motor that's a little more compact than the 1/3hp that i have, with around 3/4 hp. I don't want DC, just a simple 110v motor, I think.  I'm gonna poke around eBay to see what I can find.

Marcel


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## Ray C

xalky said:


> This is most likely going to be my next project Ray. I just finished up the rotary broach. I've been wanting a TPG for a while. I'm looking forward to the 2D drawings.
> 
> I already have the bearings here, thanks to you pointing me in the right direction on Ebay. I'm gonna study this thread and start rounding up materials for it. I'd like to find a motor that's a little more compact than the 1/3hp that i have, with around 3/4 hp. I don't want DC, just a simple 110v motor, I think.  I'm gonna poke around eBay to see what I can find.
> 
> Marcel



It's going to take me a little while to make these 2D drawings.  For the most part, the software does all the hard work but, some objects, by nature of their shape and profile are not easy to tag with dimensions and still give the reader a useful idea of the actual depths.  Several factors at play that are too difficult to describe...  Suffice it to say, it's good practice for me to do it...

Anyhow, give me a little time to draw this up so it's readable.

Ray


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## xalky

Ray, no worries on the 2D drawings. I'm pretty good at winging things on a napkin and refining it as I go. I can't figure out how you are preloading the taper bearings. I must be missing something in the PDFs. Did you take pictures of the assembly going together? That would be very helpful. 

Marcel


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## Ray C

xalky said:


> Ray, no worries on the 2D drawings. I'm pretty good at winging things on a napkin and refining it as I go. I can't figure out how you are preloading the taper bearings. I must be missing something in the PDFs. Did you take pictures of the assembly going together? That would be very helpful.
> 
> Marcel



Take a look at this PDF.  You'll see a wave spring washer pushing against the green-colored model of the radial thrust bearing.  The trick here, is that the radial shaft bearing to the right of the wave washer cannot have any play at all.  It's a dead-on fit between the shaft and the radial bearing.  That way, you only need enough pressure from the wave washer to keep the bearing seated.

Ray


View attachment WaveWasherClose-UpTPGAssembly.pdf


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## xalky

I just ordered this Workshop series Book #27 from amazon. http://www.amazon.com/Spindles-Work...ref=lh_ni_t?ie=UTF8&psc=1&smid=A3ADN03F2ABAVW On the cover is a spindle using only 2 tapered bearings, which is what I want to do. The book cost $12. I'm bound to learn a thing or 2 out of it. I've seen quite a few home made TPGs using a Router motor. I have 3 of them here, from 3/4 hp to 1hp. The RPMs are quite high on these but I think I can pulley it down to about 3000rpm.  The 1/3 hp motor I have is still on the table too. It's a bit larger than the router motors but it would be whisper quiet. The routers are noisy as hell but smaller. I'm leaning towards quiet!)

Marcel


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## drturner76

Cool Project, this is one I am working on at the moment-


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## george wilson

About using cloth over the ways: NEVER use cloth. The grit will go right through the weave. Use paper or plastic. Fold them inwardly slowly when done,and throw them away at once. Wipe everything on the lathe down anyway after removing the plastic. In fact, I'd wipe the lathe down where ever it is naked BEFORE removing the plastic.

I was surprised you found a motor that runs smooth enough to leave a good surface. Actual grinder motors are carefully balanced to leave minimal vibration.

My favorite brand of tool post grinder is Themac. I have a brand new one that is small enough to use on the Hardinge HLVH. But,it is large enough to do whatever grinding I want to do.


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## samthedog

george wilson said:


> About using cloth over the ways: NEVER use cloth. The grit will go right through the weave. Use paper or plastic. Fold them inwardly slowly when done,and throw them away at once. Wipe everything on the lathe down anyway after removing the plastic. In fact, I'd wipe the lathe down where ever it is naked BEFORE removing the plastic.
> 
> I was surprised you found a motor that runs smooth enough to leave a good surface. Actual grinder motors are carefully balanced to leave minimal vibration.
> 
> My favorite brand of tool post grinder is Themac. I have a brand new one that is small enough to use on the Hardinge HLVH. But,it is large enough to do whatever grinding I want to do.



George, I understand that grinder motors are carefully balanced, but this usually because the wheels are directly mounted to the shaft isn't it? When using a belt wouldn't much of the vibration and resonance from the motor be eliminated by the belt? Of course this will not fix an imbalanced wheel.

Paul.


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## Ray C

I was concerned about the vibration issues when I decided to use that large motor.  It wasn't my first choice but, I got sick & tired of searching for "the perfect motor" and just went with that big one.  Amazingly, the grind quality out of the one I have is really awesome...  Yes, I can feel a bit of vibration when I put my hand on the motor but, it's not very noticeable on the grinder head.  I think the saving grace was the heavy aluminum support strut/brace.  Aluminum was intentionally used for all the external chassis parts because, it's second only to cast iron in terms of absorbing vibration.  -Lucky guess on my part.

I have looked at surface ground shafts under high magnification and it looks really, really nice.  I cannot see any artifacts of vibration.

It really would be nice to find a better motor some day but, the one I have will be used until a more suitable one comes along.

BTW:  I was thinking of "mass producing" those grinder heads and selling them here on the Classified section.  I'll need to check into the "legalities" of that but, the idea is that a good donation from the proceeds would be given to this place to keep it running.  Let me know if anyone might be interested in seeing the unit I made in the classified section...


Ray


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## Bill Gruby

Do you have vibration isolators (Dampners) between the motor and the mount plate? If not, and it were me, I would use them. They go a long way in stopping even minor vibration.

 "Billy G"


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## Ray C

Bill Gruby said:


> Do you have vibration isolators (Dampners) between the motor and the mount plate? If not, and it were me, I would use them. They go a long way in stopping even minor vibration.
> 
> "Billy G"



That's a good idea and I'd try it.  I don't seem to have a problem but you know what they say "If it ain't broke, fix it till it is".   Anyhow, it does make sense and I'll do that next time I pull it off the shelf.


Ray


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## Bill Gruby

If you feel for the vibration I'll bet it is more at the lathe side of your mount. It is less rigid there than at the pivot point. The isolators will take care of that for the most part.

 "Billy G"


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## ozzie34231

I've been thinking about a TPG for a long time, especially for internal grinding. The thing that stops me is the thought of all that grit. The ways can be protected but what about the spindle?
I have a universal T&C grinder but it doesn't have any internal grinding facility. So, maybe what I should be designing is a small internal TPG grinder that could also mount on the T&C? Or, maybe just the T&C?
Ozzie


----------

