# What drives a BS-0 drive dog?



## dewbane (Sep 1, 2020)

After literally years of anticipation, I finally have a shiny new BS-0 dividing head. I took the chuck off, put the center in, and I've been scratching my head trying to figure out how the dog is supposed to drive. I figured the Chinese manual was worthless, so I downloaded a copy of the real Brown & Sharpe, only to find that the Chinese manual is actually better.

I can find endless pictures of the dog mounted on this thing, but I can't find one picture of how the dog connects to whatever it supposed to drive the thing. One of the holes in the direct index plate, I'm assuming, but how on earth?

It looks like the Chinese copy is true to the original in this respect. I can't find any pictures of the real deal performing this action either. I'm just baffled. I mean I'm not totally baffled. I can invent a solution, to be sure, but one would think a solution should already be readily available, and self-evident.

Not so much.

Apologies if I picked the wrong place to ask this. Feel free to move my post to a different forum.


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## darkzero (Sep 1, 2020)

Did yours come with the H looking bracket? I don't have one myself but from what I remember that H part is what drives the dog. The H part clamps onto the center (has a straight/non tapered section) & the center goes in the spindle taper.


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## dewbane (Sep 1, 2020)

Yes, this is a clear case of finding the answer right after asking the question. It's not like I hadn't been looking for two hours.

I finally figured it out when I thought to look at the Grizzly G1053 manual. The H-shaped six-bolt deal does bolt to the dead center as depicted in so many pictures. You need a bent leg dog to connect to this, and actually drive the work. I never would have figured that out on my own.

It so happens that I own a dog like the one depicted in their manual. I bought it for use on the g0602, and could never figure out how to interface it to the faceplate on that lathe, so I threw it in the junk pile. Ah, but didn't I finally take that junk pile to the scrapper? Yes I did. Did I scrap the dog?

Stay tuned for the exciting resolution to this question!


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## dewbane (Sep 1, 2020)

The good news is I still have the dog!

The bad news is I never used the dog, because stock has to be at least 1.5" or maybe 2" in diameter for the bolt to even reach it. This was a clear case of buying accessories for my new toys before I even understood how to use them, and that's why this dog has been relegated to the scrap bin for years. It has officially been dusted off, and summarily returned to the scrap bin.

So now I guess I'm back to forging a dog that will actually do something useful. I've been meaning to do that for years. I still haven't checked turning between centers off my bucket list, because of the Debacle of the Dastardly Dog.


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## darkzero (Sep 1, 2020)

Glad you got it figured out. Dogs can be simple to make. Lots of ideas on the net to make simple ones. I just bought a cheap set from Grizzly. They work fine for me.



dewbane said:


> could never figure out how to interface it to the faceplate on that lathe



In regards to that, faceplates aren't designed for driving dogs. They're for bolting/clamping odd parts to it that can't normally be held in a chuck. These days it seems no one makes drive plates anymore so people use faceplates. But face plates may need to be modified by widening a slot in order to fit a drive dog. Or modify the dog.

Here's my drive plate. It has 2 slots but normally drive plates have only one slot. Or they can be just a flat plate with a rod sticking out to be used with straight dogs.


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## dewbane (Sep 1, 2020)

darkzero said:


> Glad you got it figured out. Dogs can be simple to make. Lots of ideas on the net to make simple ones. I just bought a cheap set from Grizzly. They work fine for me.


The Grizzly dog I have is actually fine, it's just way too big, and doesn't fit the slot in my...


> In regards to that, faceplates aren't designed for driving dogs.


Uh. My not for driving dogs plate. Well snap.


> These days it seems no one makes drive plates anymore so people use faceplates. But face plates may need to be modified by widening a slot in order to fit a drive dog. Or modify the dog.


Or make a dog that fits the faceplate has always been my plan. There's really nothing wrong with the Grizzly dogs though. One of a more suitable size is only like $5, and I may be broke from spending $25,000 to make a $25 part, but I still have $5 by crikey I do.

So. Hmmm. The GOOD solution to this problem would be to get a hunk of cast iron, single point me some suitable threads like a real machine guy, and make a snazzy drive plate like what you showed me. What I'm thinking about instead is buying a new faceplate from Grizzly, in the hopes that the next one might not be so spectacularly crappy, and just hack up the crappy one however I see fit to make it into a drive plate.

The faceplate is definitely the weak point of my g0602. It's so ridiculously bad it's almost funny. The center isn't in the center at all. Not even close. I tried to true it up, but working on the faceplate while it's installed has obvious reach limitations, and how the heck would I work on it while it's not installed? Four-jaw maybe? I don't know. Honestly, I got frustrated with that project after covering every square inch of the shop with horrible cast iron dust. I had also just popped for a real bonafide actual lathe file, made for filing things on a lathe, of all the wonders in the known universe, and I immediately wrecked it on that stupid cast iron. Either a new Nichols file is junk, or cast iron is HARD. I'm too new at this game to know which.

Thanks for your patience though. I'm having fun. I should stop hanging out on Angry Political Rants Book, and just go back to my older self who used to make friends on forums like this, before the age of click bait media swallowed the world.

In fact, before Facebook trained me to limit myself to the 8/12th of a second attention span anybody would ever devote to anything I posted, I used to actually be a writer. I wrote a book and stuff. It had many, many pages. I think I sold at least 23 copies too. Woot!


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## markba633csi (Sep 1, 2020)

Your new Nichols file may in fact be junk. I have heard stories. Apparently, Nichols took charge and fixed it. So I heard. 
Incidentally, I have never used a lathe dog in my life.  Looking forward to it, someday soon.  Losing my lathe dog virginity. I'm tingling with anticipation
-Mark


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## Reddinr (Sep 1, 2020)

I've got a few lazy dogs in my shop too that came with the lathe I think.  Might use them some day.

Another lazy dog.


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## benmychree (Sep 1, 2020)

Dogs used for dividing head use have flat tails instead of the oval variety used on lathes, which if used on a dividing head, the setscrew used to take the slack out of rotation, will likely bind up on the rounded surface of the tail.  If the lathe dogs are not cast iron as one might expect from cheap imports, but made of steel, they can be heated to high red heat and forged down to a flat style, or one can be made in the clamp style of two pieces of square bar with a V groove to clamp the part, pinched together by two bolts near the ends and a flat bar welded on axially with the V groove to reach the clam screw on the driver (H thingie).  Be sure that the center has a flat to engage the setscrew in the driver so cutting forces do not allow it to slip on the center.


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## dewbane (Sep 1, 2020)

markba633csi said:


> Your new Nichols file may in fact be junk. I have heard stories


What actually happened in this case was I faced the plate off, which a matter of making a ton of interrupted cuts until I skinned off the high spot, and got the face flat. So that would have left the face in varying states of having the outer layer removed, with softer iron exposed where the high spot used to be. From there, I did what I could with the outside diameter of the plate. Chicka chunk chicka chunk chicka chunk. It was bad, and I was just tearing up tools while making little progress truing it up.

It was at that point that I produced the brand new shiny lathe file, with the intent to round over the sharp corner I had just turned. I've used a standard file on the lathe to do similar jobs plenty of times, and I'm sure there was nothing particularly crazy about my technique. It was, admittedly, a much larger workpiece than the last thing I rounded over with a file, but still, I don't think that explains the damage.

When we were kids, we used to be unintentional hooligans. There was a row of industrial air conditioning units along the side of a building at the end of the street, and we used to draw random things by taking a stick to the heat exchanger fins. It still makes me wince to think about that today, but it is what it is. Well, that's what the file ended up looking like after this operation. The teeth are just, well, gone. You can see little arcs in the teeth that show the path of every stroke.

I guess when I look at it again, I'm thinking it looks like I tried to file some kind of grinding wheel. Now, I'm not metallurgist or anything, but if I was able to remove material from that plate at all with any kind of lathe tool, then it can't have been THAT abrasive or hard. If I tried to use carbide or HSS to true up a grinding wheel, I feel like I would have a pretty good idea some grinding was going on, with little sparks shooting out and so forth. None of that happened here. The faceplate just wrecked the teeth on the file very unceremoniously.

I'm going to go with the opinion that I think the file is just junk.



> Incidentally, I have never used a lathe dog in my life.  Looking forward to it, someday soon.  Losing my lathe dog virginity. I'm tingling with anticipation


Neither have I. If I beat you to it, I'll have to post pictures. I actually did order a replacement faceplate and a couple of the factory dogs in smaller sizes. I can move forward with the plan to turn the original junky plate into a drive plate. Especially if the replacement is closer to running true. Who knows. My experience so far is that Grizzly replacement parts tend to have better chances of passing some quality control tests than the parts that ship with new Grizzly machines. I am hopeful.


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## dewbane (Sep 1, 2020)

Reddinr said:


> Another lazy dog.


Your shop puppy reminds me of a day that still makes me feel kind of bad. I don't have a good way to access photos from here, so I'll have to post my shop dog some other time. She's a great dane boxer mix, and I got her a memory foam dog bed for the shop.

I had been trying to machine the top of a piece of railroad track for years, and I broke a lot of tools along the way while making a real mess of it. I finally got one of those carbide insert face mills. I went to town on the track, and that thing was just going to town like a champ, and leaving a beautiful surface finish to boot. Finally!

That's when I realized it was also throwing extremely wicked little blue C-shaped chips all over Her Majesty and her fancy new bed. Poor puppy!

Poor shop too, and poor beard. I was digging those chips out of my beard for a week. I  really need to build some kind of acrylic enclosure before I use that tool on anything again. It makes a much larger and nastier mess than any other machining process I have yet encountered.

I finally got the railroad track anvil done though. About four years after I bought a real anvil, so I don't even need that one, or use it for anything. But the top is flat and shiny. So I win!


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## benmychree (Sep 1, 2020)

The trick with cast iron is to get the point of the tool UNDER the hard scale on the first cut and use a relatively fast feed and moderate cutting speed.


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## WobblyHand (Feb 20, 2021)

Yes, I realize this thread is a bit stale, but same problem.  @dewbane Question is: do the Grizzly small bent tail lathe dogs actually fit the the BS-0 they sell? Practically none of the bent tail lathe dogs I've seen have any dimensions on them, save for the bore.  The BS-0 I have, has an H carrier that is only 82mm long from end to end.  If the tail isn't bent close to the carrier, it won't be captured by the H.  Guess I could fab one from a ring and weld a flat tail on it.  It's getting kind of meta, I'm making tooling to make fixtures, so I can use the tooling I bought, to actually making something. Perhaps I'm too impatient.  Were you able to actually use your BS-0 on centers?  If so, what did you end up doing?


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## benmychree (Feb 20, 2021)

Lathe dogs are not meant to be used with milling machine dividing heads, which require dogs with flat tails.  If your lathe dog is made of steel  rather than cast iron, you can forge down the tail and bend it so that the setscrew on the driver can bear against it, but even then they do not work really well because of binding due to any slight misalignment between the dividing head and its footstock. I solved this problem in the case of my #2 B&S dividing head by finding a Red E Dog driving device, which consists of a taper shank with attached bracket with a hollow radiused slot running parallel to the shank that receives a ball with a hole running through it that receives a round shank attached to a clamp driving dog that carries the workpiece; every part of it is finely fit so there is no backlash, and no binding.


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## benmychree (Feb 20, 2021)

Here is another approach to the problem, this could be easily made in the home shop;








						The Cincinnati Milling Machine Company, Manufactures of Milling Machines and Cutter Grinders
					





					books.google.com
				



I think I misidentified the driving dog setup that I spoke of in the above post, Red E Dog makes cylindrical grinding dogs, not milling dogs.


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## benmychree (Feb 20, 2021)

I was right after all, it was made by the Red E Tool co.  Here is a link to the catalog with a view  of the driving dog setup.




__





						red e tool co. - Google Search
					





					www.google.com
				



The image appears in the second row down, at the left image.


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## WobblyHand (Feb 20, 2021)

@benmychree that ebook was quite interesting.  I don't understand how that milling dog works yet, much less make one like in the picture.  Too inexperienced to understand it yet.  If I'm following the picture, there's a straight tail dog, perhaps with an offset, and a clamp assembly that allows some minor rotation of the dog tail?  The assembly then is retained by the drive?  Sorry, I don't even have the vocabulary to describe it precisely.  I was looking at the ebook on my phone and the picture was not too clear.  

One thing I did notice was the prices for these accessories.  65 cents for a 1" tool!  I'd pay that!


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## benmychree (Feb 20, 2021)

The Cincinnati one looks easy to make, the block is fastened into the "H" with a stud and nut from the back of the H, it carries two adjustable blocks on either side of the leg of the dog  so that the adjustment can be made to fit snugly, or I suppose one block could be made solid with the base block and the other one made adjustable.  I think if you see it larger than your phone allows, it will be clear as to how it works.
The Red E tool is more elaborate but is a better design in several ways; since neither are available commercially any more, the simpler Cincinnati design would be the thing to copy.


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## WobblyHand (Feb 20, 2021)

Viewing on a larger screen does help.  On the jaws of the clamp of the dog, would they have a circular profile cut to help hold the round dog tail? Or a V notch?  Goodness, falling deep into the rabbit hole!  Not sure how I'd do it yet, but it seems possible (for me).   Now to figure out how to sketch up the pieces.  Looks like I have to make the offset dog.  Can the offset dog be made of a lathe turned ring with a round rod welded to it?  1018?


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## benmychree (Feb 20, 2021)

The dog tail would fit between two flat surfaces so that it could move in and out to avoid binding, but the two jaws need to fit snugly against the tail to avoid backlash.  A turned ring would not seat well against round workpieces; better would be two rectangular bars with vee notches centered on their length and clamped together with bolts near their ends, the tail could be mounted to one of the bars in a tapped hole.  For the clamping holes, one should be tapped, and the other clearance drilled.  The tail of the dog need not be offset, if the block that fastens to the "H" is tall enough.   I made such a clamp dog for the first Red E setup that I had, where the dog parts were missing, but may years later I found a new complete unit on E Bay, which I use nowadays.


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## dewbane (Feb 20, 2021)

WobblyHand said:


> Were you able to actually use your BS-0 on centers?  If so, what did you end up doing?


I ended up using the 3-jaw on my test gears, and just kicked the can down the road. My test gears were just test gears.

My shop is still in an unheated space, and the weather finally shut me down. I started working on a plan that ends with me moving the shop inside my house, which will solve all my rust problems, and allow me to work any time of the year, but the weather shut this plan down too. I really don't want to move a 600 pound lathe in the snow, and the snow has been around forever this year.

I'll get there one of these days!


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## benmychree (Feb 20, 2021)

Thinking more about this, I think that as long as the tail of the dog that I have suggested fits nicely in the block fastened to the "H" driver, there is little need to make it adjustable.


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## benmychree (Feb 20, 2021)

Where in Va. is Christiansburg? My wife came from Derby Va. a mining camp not far from Bristol, Va.


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## WobblyHand (Feb 20, 2021)

benmychree said:


> The dog tail would fit between two flat surfaces so that it could move in and out to avoid binding, but the two jaws need to fit snugly against the tail to avoid backlash.  A turned ring would not seat well against round workpieces; better would be two rectangular bars with vee notches centered on their length and clamped together with bolts near their ends, the tail could be mounted to one of the bars in a tapped hole.  For the clamping holes, one should be tapped, and the other clearance drilled.  The tail of the dog need not be offset, if the block that fastens to the "H" is tall enough.   I made such a clamp dog for the first Red E setup that I had, where the dog parts were missing, but may years later I found a new complete unit on E Bay, which I use nowadays.


I don't understand your first sentence.  In the drawing, the dog tail is round.  If one has flat jaws what prevents the round piece from popping out especially if there is tilt?  Won't the jaws tilt outward towards the dog tail?  How is the round tail held in figure 2, in the link you provided?

Understand the rest, especially about the dog.  Was hoping for something easier, but the two piece dog is ok.  I'll have to come up with a way to do a reliable V.


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## WobblyHand (Feb 20, 2021)

dewbane said:


> I ended up using the 3-jaw on my test gears, and just kicked the can down the road. My test gears were just test gears.
> 
> My shop is still in an unheated space, and the weather finally shut me down. I started working on a plan that ends with me moving the shop inside my house, which will solve all my rust problems, and allow me to work any time of the year, but the weather shut this plan down too. I really don't want to move a 600 pound lathe in the snow, and the snow has been around forever this year.
> 
> I'll get there one of these days!


Was hoping you'd show me how it's done!  No problem.  I could cut some gears with the 3J as well, just to work out some of the basics.  I do need to figure out this mandrel stuff to make real gears though.  

My shop is in my basement and it's relatively cold at 55F.  It's ok for short periods of time if I dress up.  I need to wire in 220V so I can get a real heater in to make it more habitable.  One more item to add that to the ever growing project list!  Now that I think about it, I'm going to bump the wiring up in priority - too cold to enjoy working down there.


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## benmychree (Feb 20, 2021)

There would normally not be tilt, the dividing head would be swiveled upwards so that the center of the part would be inline with the center of the dividing head, and the footstock would also be raised and in alignment with the part centerline, although I do not know if the BS-0 footstock has that capability, and this would not be necessary for normal work, only work that is tapered in the cutting path.  The main reason for the dog system is to avoid the binding that normally accompanies the use of driving dogs between centers when the setscrew on the "H" driver is tightened against the tail of the dog.  The binding is avoided by having the opportunity for a small amount of float axially in the jaws of the driving block


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## benmychree (Feb 20, 2021)

WobblyHand said:


> Was hoping you'd show me how it's done!  No problem.  I could cut some gears with the 3J as well, just to work out some of the basics.  I do need to figure out this mandrel stuff to make real gears though.
> 
> My shop is in my basement and it's relatively cold at 55F.  It's ok for short periods of time if I dress up.  I need to wire in 220V so I can get a real heater in to make it more habitable.  One more item to add that to the ever growing project list!  Now that I think about it, I'm going to bump the wiring up in priority - too cold to enjoy working down there.


Yes, cold really does take the fun out of shop work!


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## WobblyHand (Feb 20, 2021)

The BS-0 footstock is somewhat adjustable, although it seems to be a bit fiddly and prone to error.  If I recall the point is set to the center of rotation of the head, (dimple in the side of the head) and one needs to raise the footstock so it's level as well.


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## WobblyHand (Feb 20, 2021)

Back to my jaw question, would a vee in the jaws be a help or a bad idea?  Once I'm set up to do a vee, might as well do a bunch of them...


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## benmychree (Feb 20, 2021)

In their book "Practical Treatise on Milling and Milling Machines" they show a simple tool with a ring that slips over the dividing head center and attached to it is a straight edge blade that projects some distance and the top of  footstock center is brought up to bear against it to bring it into close alignment with the headstock center.  The book shows a picture, but nowhere in any of the catalogs is one illustrated for sale, so I suppose that one had to make it for themselves.  I have never had much need for one, and never made one.  Another thing that they show in one of the books is an extension handle that fits over the dividing head input sector handle that increases the cranking radius so that cranking is made easier when using the head for rotary milling, such as when making screw machine cams; likewise it does not appear in catalogs.


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## benmychree (Feb 20, 2021)

WobblyHand said:


> Back to my jaw question, would a vee in the jaws be a help or a bad idea?  Once I'm set up to do a vee, might as well do a bunch of them...


A vee in the jaws would defeat the purpose of the jaws, which is to allow a bit of axial movement between the jaws.
My wife thinks that Christiansburg might be near Radford where her sister went to college --- ?


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## WobblyHand (Feb 20, 2021)

@benmychree, I don't understand the expression axial movement between the jaws.  Axial movement of which element? the dog pin, the bolt through the H, the mandrel, or the bolts for the jaws?  There's quite a few axes in the picture.  I was thinking of a vee that was along the dog pin axis.  Would that vee restrict axial movement?  The vee would restrict radial movement.  

Christiansburg is SSW of Roanoke, off I81, not too far from Radford.  Your wife has a good memory.


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## benmychree (Feb 20, 2021)

What I am talking about is the need not to restrict the motion of the dog tail in a direction either in or out of the slot towards or away from the headstock.  
My wife has been in Ca. since about 1962, but has been back in Va. many times since then, and I have been back there a number of times as well; her folks brought her out here back then, as he was offered a job and living accomodations by an aunt whose husband was a partner in a boiler shop in San Francisco, but lived in Napa, where she and I attended high school. eventually he retired and they moved back to Bristol where my wife's sister and family lived, that being after my wife and I were married in '72.  They left Va. because of a downturn in coal mining, her father being a foreman in the Derby mine.


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## dewbane (Feb 21, 2021)

WobblyHand said:


> Was hoping you'd show me how it's done!  No problem.  I could cut some gears with the 3J as well, just to work out some of the basics.  I do need to figure out this mandrel stuff to make real gears though.


I don't know if the setup I put together will be good enough or not. I turned a rod with center divots on either end that unscrews, with a couple of hexes machined so it can be tightened. It takes a gear blank with a reamed 1/4" hole, and holds the blank through a combination of the center hole fit and compression. I made this on the 3-jaw on the lathe, flipping it end for end, so it's not perfect. Is it good enough in practice? I think it probably is for my purposes. I'm sure if I indicate the runout on any of the gears I've made, it will be very measurable, but will that actually impede their function? Maybe I'm too cavalier, but I think this setup will probably be fine.

My shop is currently at 13℉. We had a ton of ice the other day. Basically everywhere in 200 miles in every direction has thawed out, but lucky me, I still have substantial ice on all my trees. Spring seems a distant daydream at this point.

Anyway, sorry I haven't worked through things far enough to have the between centers deal worked out. It's on the someday list. Someday after I get the shop moved. I really wish I didn't have to move the shop. I like the setup a lot, and I have so many problems to solve in moving it.


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## dewbane (Feb 21, 2021)

benmychree said:


> My wife thinks that Christiansburg might be near Radford where her sister went to college --- ?


That's the place, yes. I went to college in Radford as well.


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## WobblyHand (Feb 21, 2021)

dewbane said:


> I don't know if the setup I put together will be good enough or not. I turned a rod with center divots on either end that unscrews, with a couple of hexes machined so it can be tightened. It takes a gear blank with a reamed 1/4" hole, and holds the blank through a combination of the center hole fit and compression. I made this on the 3-jaw on the lathe, flipping it end for end, so it's not perfect. Is it good enough in practice? I think it probably is for my purposes. I'm sure if I indicate the runout on any of the gears I've made, it will be very measurable, but will that actually impede their function? Maybe I'm too cavalier, but I think this setup will probably be fine.
> 
> My shop is currently at 13℉. We had a ton of ice the other day. Basically everywhere in 200 miles in every direction has thawed out, but lucky me, I still have substantial ice on all my trees. Spring seems a distant daydream at this point.
> 
> Anyway, sorry I haven't worked through things far enough to have the between centers deal worked out. It's on the someday list. Someday after I get the shop moved. I really wish I didn't have to move the shop. I like the setup a lot, and I have so many problems to solve in moving it.


No need to apologize!  Life happens.  I was only kidding, but it didn't come through very well.  My fault.

Your shop is like my unheated garage.  In the winter, basically I can't do much work there.  I had a 220V heater which helped, but everything I was working on was stone cold, tools, metals, everything that I had to touch.  It was really had to work there.  My fluorescents lights ran dim due to the cold.  I've fixed some of that, but it's just too cold to work in and not be miserable.   Here in S.NH we have a foot of snow on the ground.  I don't remember when I last saw the ground.  Fortunately - so far we haven't had much ice.  I sympathize with you, as ice is awful.  It causes a lot of destruction and is difficult to get around in.  A few years back we had a bad ice storm and lost power for a week.  It was really hard to keep the house from freezing the pipes.  (Believe me, you never want to experience that.  A freeze over causes an unbelievable amount of destruction in a home.) I had to work round the clock to feed a small coal stove to get some heat in the house.  It was very warm near the stove, but pretty darned cold at the ends of the house.  Not good times at all. 

My shop is in an unimproved basement, dug in 1851.  It's primitive, and has air leaks.  I've been trying to patch the cracks in the stone walls with lime mortar as time permits, but I've got a lot more to go.  There's a draft there that I haven't found yet near the ground.  So at 4ft the thermometer reads 55F, at 1ft it's like 35F.  Even though I have a rubber pad by my machines, the drafty cold seeps into my feet.  Today I'll measure out the run for 220V and figure out how much romex to buy.  It's messy work in an old basement, but it needs to be done to make the workspace a little more habitable.  Once it's more temperate down there, I plan to re-organize the space, as it's far from optimal.  

I understand the someday list all too well.  Have far too many items on that list.  There are times when you just have to grab an item off that someday list and stick it in today's list. Otherwise, that event won't ever happen.  So I'm picking one thing and trying to get it done.  My one thing is 220V.

Spring will come.  It's not that far away.  By April it will be a lot nicer, especially in VA.  That's only 5-1/2 weeks


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## benmychree (Feb 21, 2021)

dewbane said:


> I don't know if the setup I put together will be good enough or not. I turned a rod with center divots on either end that unscrews, with a couple of hexes machined so it can be tightened. It takes a gear blank with a reamed 1/4" hole, and holds the blank through a combination of the center hole fit and compression. I made this on the 3-jaw on the lathe, flipping it end for end, so it's not perfect. Is it good enough in practice? I think it probably is for my purposes. I'm sure if I indicate the runout on any of the gears I've made, it will be very measurable, but will that actually impede their function? Maybe I'm too cavalier, but I think this setup will probably be fine.
> 
> My shop is currently at 13℉. We had a ton of ice the other day. Basically everywhere in 200 miles in every direction has thawed out, but lucky me, I still have substantial ice on all my trees. Spring seems a distant daydream at this point.
> 
> Anyway, sorry I haven't worked through things far enough to have the between centers deal worked out. It's on the someday list. Someday after I get the shop moved. I really wish I didn't have to move the shop. I like the setup a lot, and I have so many problems to solve in moving it.


For gears that are going to be used, they should be concentric with the bore, the finer the pitch, even more so.  Your arbors should be quite concentric with the center holes, at least, the portion that the gear blank seats on, to that end, they should be turned between centers to ensure concentricity.


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## dewbane (Feb 22, 2021)

benmychree said:


> For gears that are going to be used, they should be concentric with the bore, the finer the pitch, even more so.  Your arbors should be quite concentric with the center holes, at least, the portion that the gear blank seats on, to that end, they should be turned between centers to ensure concentricity.


Oh, I get that they *should* be, but I have yet to successfully drive anything between centers, so I improvised. I think it might work well enough for my purposes. I should mount the gears I've already made on some rigid test stand and measure how big the error actually is.


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