Clausing 100 Series gears

T

TorontoBuilder

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I have a quick question I hope someone with this model lathe can answer.

I've been asked to make a set of change gears for one of these lathes. The person has told me the following specifications:

16DP, (14-1/2PA- or 20 will work)
11/16 bore with 1/8 keyway,
with the following tooth counts; 16/32x2/40/44/46/48/52/54/56/60/64
1/2" thick

I would like if someone can verify this for me, I could not find this with a quick google search. I'd also like to know if you'd recommend making these in delrin as the person wants. Or something else.
 
Very likely the original gears would have been 14 1/2 deg PA, and 20 deg would not mesh with any gears that you might have, personally, I would not like to have delrin gears because a jam up might destroy some of the gear train, they may run more quietly, but that is not a high concern for me.
 
I run a Craftsman, Atlas built, 12X36 of almost antiquity, 101.27440 I think an ancestor to the Clausing line. The gear specifications you list sound very much like my machine. I won't say they are the same, but it sure sounds like it.

First off, 14-1/2 degree pressure angle will not mate with 20 degree gears. Almost, but not quite. . . On my Atlas built machine, the gears are 14-1/2 PA. The list sounds like a threading train, indicating that there will be at least two attached to the machine proper that must be meshed with.

Re. Material: I use aluminium for most of my machine gears. I do a lot of modeling where plastic is suitable, but they are modulus 0.5 and smaller. Full size gears are done in aluminium. But I'm an old school buzzard, for what that's worth. I am told that plastic is suitable for change gears. There is little torque, they can be thought of as timing gears, not power transmission. Making them as pairs, one alum and one plastic on the same mandrel would not take much more time and certainly make you feel better about the job. And may well improve your standing/pricing with the end user.

Delrin seems to be the preferred choice of plastic for making change gears. I made one, a 127 tooth, mostly to prove my fixture worked. I finagled a fixture using a Modulus 1 as a pattern. I'm not sure what type of plastic, but I know it wasn't delrin. Just some scraps I had on hand. The gear was to do true metric threading conversion on my Atlas built machine. I've only done it a couple of times, normally I use change gears for an "almost, but usable" configuration.

Not the answer you were looking for, but just my opinion.

,
 
Thanks Hudson.

I suspected the sizes were correct and I'd known that 14 1/2 PA was the norm so it alarmed me that the person said 20 would also work. Thankfully I have 14 1/2 pa 16 dp cutters so that is a moot issue.

I will be making my own gears at the same time where I need dura-bar G2 so that's what I'd have used, but the person seemed to prefer plastic. I recommended delrin since I know it would machine very well and run quietly.

I'm only charging for materials. I also offered to allow the person to use our shop under supervision to make their own if they wanted the experience and bragging rights that they totally rebuild their own lathe. If I had the material I'd not even charge for it.. I like helping people get a lathe working
 
Be careful letting people into your shop- there's that liability issue with lawyers just waiting around the corner to pounce
 
markba633csi said:
Be careful letting people into your shop- there's that liability issue with lawyers just waiting around the corner to pounce
Click to expand...
Dont I know it. When my brother and I were struggling to maintain a suitable space for our hobby shop and to actually grow it out one of the things we considered was starting a industrial maker space and charging people for membership and machine rental fees. I can actually get insurance for that. I can't afford the costs of commercial real estate in Toronto.

I'll have them sign a waiver, because we always invite people over to chat and learn.
 
I also have a Clausing 100 MK standard lathe with some of the change gears missing. I saved the tooth count you posted as future reference for myself. I plan to make mine out of cast iron. And because cast iron of that diameter is hard to find and expensive as heck, I plan on doing an e-Bay search for old used cast iron change gears that I can turn down for blanks and re size the bore for the sizes I need. You can often pick up a set of unknown cast iron gears cheap. I love repurposing
 
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