Advise on draw bar for 5C collets?

brasssmanget

brasssmanget

Active User
H-M Supporter Gold Member
I'm going to make a draw bar for my 10L, and I have the threaded tube, a rear wheel, and a set of crush washers to use if needed. I'm waiting on some aluminum stock to turn down a filler for the back end of the tube to fit the flange in the spindle.

My question is this. Is it wise to use a crush washer to help alleviate some of the torque pressure put on the rear spindle, and does it help with unscrewing during operation? I've read that some bars get loose during operation from the spin of the spindle going the same rotation as the threads of the draw bar/collet rotation. Am I explaining this correctly? The wheel portion is 3/4" turned plate, so it's pretty heavy in itself. Any input would be appreciated.
 
I made a closer for my 12X36 chinese lathe and used a 6.5" cast iron hand wheel. Had trouble with the collet loosening. I replaced the wheel with a plastic one 5.5" and have had no more problems. I did not use the Belleville washers but I did use a needle thrust washer. A pair of Belleville washers would probably improve the holding ability of mine although I am not having any issues so far.

Joe
 
i have a Royal handwheel-type 5c closer, back-when they used to make them custom to your lathe....it has a sturdy but lightweight (low inertia) handwheel, thrust bearings, and holes in the shaft for a pin wrench to be used to snug up the shaft more that what you can do with the handwheel alone. The key part is the collet adapter which holds the collet itself, that part looks like it took some real precision making....
 
Thanks for the replies. I guess I may have to rethink the wheel portion and go with a lighter material. It's a work in progress. ;)
 
Too stubborn to quit!

Well, I went ahead and completed what I had started. I figure I can always adjust and re-invent the wheel so to speak. Thought I'd share what I did so others can at least get some ideas, be they good or bad. :eek:

For starters I just made up my mind to finish what I had started. I'll de-burr some of the holes and slots tomorrow and try it out to see how well it stabilizes under power, and go from there. May take some advice and remake the spacer sleeve in a heavier material. There is a thrust/needle washer at the rear between the spacer and the wheel. This whole assembly just floats on the bar, but should remain snug when tightened to the collets. Five 10x32 screws hold the wheel to the bar.

Anyhow, here's kinda what I did to try and lighten the steel wheel, but I think it may still be on the heavy side. We will see :)
 
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Thanks Ziuck. As tempting as that is, I'm going to see this one through with home made parts if I can. Up until about 6 weeks ago I had never even seen a metal lathe, much less worked with one, so this is kind of an on the job training thing for me. I have a long ways to go, but I'm enjoying it.

I did get a chance to run the lathe this morning with some 5C collets using the draw bar. It worked pretty well, and never really came loose to the point of losing grip with the collet, but I did notice it went from quite snug to maybe a 15-20 degree (turning radius tightness) change of the wheel after about 1/2 hour of spinning. I'll spend some more time in the near future and see if it loosens any worse than that with extended use. If it does, well, there's always alternatives! :)

All in all I was pretty pleased. It had very negligible wobble, and the holes in the wheel made it easy to torque down on the collets. It even looks good on the SB - what more can I ask at this point? :biggrin:
 
Digging this up from the grave. :)

Hey Brass, you've given me inspiration to attempt one for my 10L. Would you mind measuring (or do you know) the length of the drawbar for your 10L? Thanks.
 
I made this one HERE

I was going to use a large diameter cast iron wheel, then I realized that turning the lathe on would probably us-screw it due to it's mass.
That was when I made a smaller aluminum wheel.

I also used a thrust bearing against the spindle.

Works great.

Gary
 
Splat said:
Digging this up from the grave. :)

Hey Brass, you've given me inspiration to attempt one for my 10L. Would you mind measuring (or do you know) the length of the drawbar for your 10L? Thanks.
Click to expand...

I'll check it when I'm in the shop later - pretty sure it was 11.50" +/-, but it wasn't critical for my setup as the tube fit through the wheel portion, and I was able to cut to length after fitting it all together and screwing on a collet.
 
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