back gear 10L...

tony_southbend10 · Feb 26, 2009

I've reinstalled the back gear in my 10L last night. It was pretty straight forward. The tapered pin that I destroyed taking out was replaced quite nicely by a 1 1/2" #2 pin that I got at the hardware store.
Now I have two Q's:
1) it seems to me that there is a lot of forward-backward (along the axis of the lathe) play. When I say "a lot", I mean about 1/8". Is this normal?
2) how easily should the back gear spin by itself?
Thank you all!
Tony

10KPete · Feb 26, 2009

Well, I can't answer the first question but as to the second, if there is no oil or grease in the back gear assembly it should spin freely. That's what mine does/did and I just can't imagine any reason for the bushings to be tight.

Pete

tony_southbend10 · Feb 26, 2009

I just measured the play again, and it's pretty much exactly 1/8": the front bushing can be flush with the casting, but can also be pushed out (to the left) by 1/8"...

The gear spins OK, but it's not like if it was on ball-bearings: it might spin 1-2 times if moved by hand.

My worry is that when I drilled out the tapered pin that was in the front bushing, I might have off-set something...

flathead4 · Feb 26, 2009

Tony,

I couldn't tell from the drawing I have so I went out and pulled my back gear. As I suspected, there is a groove in the left bushing that the set screw rides in. The set screw and jam nut should limit travel if adjusted correctly. Try screwing the set screw in a little more.

Tom

tony_southbend10 · Feb 26, 2009

Tom,
Thank you so much for your answer and the photos! I took my back gear apart again.
It looks like the set screw that you show in your photos is actually a set screw + a cylindrical pin (about 9/32" long). Now I almost think that the my set screw actually broke into the screw part + the pin?
This would explain why I simply cannot get it right. Maybe I need a new set screw? Or I can just use a larger pin as a set screw?
Tony
PS. would you mind measuring your set screw? now that I think about it, maybe it will be best to turn my own... thank you!

flathead4 · Feb 26, 2009

Tony,

How's this? The screw itself is 5/16 X 24 TPI. Both ends are radiused.

Yeah, I'd just make one. Maybe you have a suitable bolt laying around that you can cut the head off and slot it with a Dremel. Then just turn the treads off the other end.

Tom

tony_southbend10 · Feb 26, 2009

Tom,
Thank you so much!

I really appreciate your help - I will look for a bolt in the hardware store tomorrow, and cut a slot with a Dremel.
Tony

flathead4 · Feb 26, 2009

If you get a long enough bolt, you could leave the head on and not have to fool around with a screwdriver. Not "original" but maybe more functional.

Tom

10KPete · Feb 27, 2009

Ah ha! That pin is what restrains/sets the axial motion of the shaft. Learn something new every day!

Pete

flathead4 · Feb 27, 2009

It's pretty convenient that I have a 10L headstock sitting on my bench that we can use as a learning aid.

Tom

tony_southbend10 · Feb 28, 2009

Quick update.
I took a long 5/16 X 24 bolt, cut the head and turned one end down to 0.25. It was still a bit too large, 0.248 seems to work better.
Now it's in, and the lever turns about 90 degrees. Is this about right?
Thank you!

SBLatheman · Feb 28, 2009

That screw is used as a stop for the engagement of the back gear. Adjust it so that you have the proper backlash in the gears when you pull it in.
TED

10KPete · Mar 1, 2009

What Ted said! That part I know about.

Pete

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