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11.5 tpi

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neilking

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#1
can I use a threading dial to cut 11.5 tpi?

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Bob Korves

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#2
You will need to tell us more to get a useful answer. What lathe? Metric or Imperial lead screws? Do you have the correct change gears (if needed) to do 11.5 tpi? Will the 11.5 thread be straight or tapered? What are you making?

Edit: Answering the following questions might also help your project. Will the thread be required to seal against gaseous or liquid pressure without leaking? If so, how much pressure?

My Kent USA 13x40 with a 8 TPI lead screw, 4" per revolution threading dial, and 32 tooth threading dial gear can be used for 11.5 TPI if always engaged on the same number.
 
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rock_breaker

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#3
If you have a 11.5 square on your quick change on your lead screw gear box Yes. I am sure the machinists that change the gearing on the end of their lathes will have some interesting comments on this. I say yes with out going out to the shop to check the threading chart on the Clausing but I am reasonably sure it has an 11.5 setting. I re-read your question thus the following comment I would use the same number on the threading dial for each pass. Are you cutting internal or external threads? Maybe both so enjoy. Please excuse the jump to conclusions at the beginning of this response.
Have a good day
Ray
 

RJSakowski

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#4
My Grizzly G0602 will cut an 11.5 tpi thread. The thread dial will work with any two marks diametrically opposite each other (1 & 7, 2 & 8, 3 & 9, 4
&10, 5 & 11, or 6 & 12).
 

Rooster

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#5
I would just chuck up some scrap and find out.
 

neilking

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#6
southbend 9b, 8tpi lead screw. I ruined this by cutting left hand threads.


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bfd

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#7
yes just use the same number each time. this gives you the same place each time bill
 

neilking

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#8
Thanks!

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benmychree

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#9
Can't say for others, but my 19" Regal will cut 11-1/2 TPI, and will engage properly on opposite numbers on the thread dial; only if there are quarter threads, do I have to engage on the same number; this applies to any lathe with a 4 TPI lead screw.
 
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benmychree

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#11
This is essentially the same as for my lathe and my earlier comments
 

neilking

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#12
update. The threads are not perfect but will work for 4 threads


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P. Waller

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#13
11 1/2 is a common NPT lead, every inch lathe ever made will have gearing for this,. The NPT standard was developed in 1864, I suspect that your machine is not older then that (-:
 

brino

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#14
The threads are not perfect but will work for 4 threads
That looks like success to me!

Nice knurl on the grip edge.
I notice one is left and one is right.......did you do them in different orientations, or with different tools?
-brino
 
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neilking

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That looks like success to me!

Nice knurl on the grip edge.
I notice one is left and one is right.......did you do them in different orientations, or will different tools?
-brino
good question. When I figure it out... Same tool. Same rotating...

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neilking

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#16
11 1/2 is a common NPT lead, every inch lathe ever made will have gearing for this,. The NPT standard was developed in 1864, I suspect that your machine is not older then that (-:
I had the gears, just hadn't used the threading dial I had installed before. Opposing odd numbers worked great. Even figured out how to remove the work piece from the chuck, put it back in the chuck and align the threads to continue cutting

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jdedmon91

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#17
The poster that suggested using one number made sense. If you are not sure which way to use #1 and you always be correct


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