Thread Dial...

P

plongson

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I have a circa. 1962 SBL 14 1/2" x 96" lathe and finally got it all cleaned up and running very well. I've been using it and getting familiar with it...
Something I have not been able to find is a definitive explanation or technical sheet on the thread dial.
I've seen details on even thread/ odd thread/ divisible by 4/ not divisible by 4...yada-yada...it's making me crazy.

Is there one publication on this lathe that describes the correct use of the dial for this lathe?

I would be forever in your debt!

Paul
20220615_175033.jpg
 
Please be advised. I had a 13" SB lathe.
When I cleaned up the thread dial, I took it apart, cleaned, oiled, painted (not necessarily in this order :))
When I put it back together I realized my mistake. I did not mark the original position of the shaft to the dial.
I used it, adjusted here a bit then locked it down. Worked great.
Isn't it fairly standard on these dials where an odd number use a number and even use any line?
 
The proper use of a thread dial is determined by the lead screw pitch and the number of teeth on the thread dial gear. Most likely, you have an 8 tpi lead screw and 32 teeth on the gear. The number of teeth can easily be determined by the distance the carriage moves for one complete revolution of the dial.
 
Best advice for a Sout Bend lathe owner may be to buy a copy of "How to Run a Lathe", published by The South Bend Lathe Works, it will give info for their particular lathes. I doubt that that size lathe would have an 8TPI lead screw, nor a 4 TPI, most likely, I think is 6TPI, this does effect some of the info above that is suited to 4 TPI, which is most used on mid size industrial machines.
 
Checking the lead screw is the first place I'll look, then I'll have a better chance...
 
Yep, 6 tpi and 24t gear...
Just checked
 
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