Need advice for cutting #12-20 threads

WCraig said:
Do you mean Stanley planes? These planes were designed well before the development of the now-ubiquitous UNC/UNF/UNS thread forms. See discussion here, for example:

OldTools Archive

swingleydev.com swingleydev.com

Plus these planes were in production for many decades. The specifications and tolerances likely changed a fair bit from the beginning to the end.

All that said, it seems that for the few threads engaged in the boss on the plane body, 12-20 UNS is good enough in most cases. The retaining nut engages more threads and may not be as forgiving.

Craig
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Hi Craig, yes I have all the old info on the original thread sizes. I would have to double check but I think my die is UNS and the resulting thread works.
 
mwebster51 said:
Thanks Bill I will save your message and down the road I may take you up on that. I am new to this forum, do you have private messaging for communication like phone numbers and addresses?
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Yes, we do, and I just sent one to you. You should see a red number next to the bell image in the upper right hand corner of the screen. Press the bell, and my PM will appear.
 
Put a .218 mild steel rod in a drill and reduce the size to .216" with sandpaper. Taper the end ⅜" gently, not just a chamfer (make longer and cut this paft off if required). Go at it with the die. If the die isnt straight it will be harder. You can guide it with a drill press.
 
bill70j said:
FWIW

In case you were to take me up on my offer, I wanted to make sure I could come through - So I just cut some 12-24 threads out of 0.25" diameter O-1 drill rod, which I turned down to 0.2160".

I did it both ways - first by single-pointing on the lathe, then by using a "re-threading" hex die.

Both methods produced acceptable threads, though I prefer single pointing since you can control the fit.

But what surprised me was how well the die performed, considering this discussion. I wonder if your 12-20 die is dull?

Anyway, here are a couple of photos of this morning's activity.

Here is the hex die I used. It came out of a vintage Craftsman set I have had for years. (Sears sold them as thread cutting dies, but many claim they are acceptable only as thread chasers.)
View attachment 309299

Here is the tailstock die holder. I used it under power, with no problems with engagement or with cutting.
View attachment 309300

Here is the single point threading set-up
View attachment 309301

And here are the threads. Not pretty, but they work.
View attachment 309303
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It is possible the die has gotten dull, I have another new one on order, it may help.
Yeah looks like your techniques would work... Thanks for doing some testing. My die is circular though.. anyway... I may take you up on your offer, Things are still pretty busy with holiday family stuff, and I would need to get some more rod material.... but thanks. How would I contact you?
Mark
 
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GrayTech said:
Put a .218 mild steel rod in a drill and reduce the size to .216" with sandpaper. Taper the end ⅜" gently, not just a chamfer (make longer and cut this paft off if required). Go at it with the die. If the die isnt straight it will be harder. You can guide it with a drill press.
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Thanks GrayTech, I will put that in my arsenal of possible solutions.
 
Thanks guys for all your suggestions, I need to get to work so responses won't be for a while, I think I have plenty to think about and maybe Bill can help me out locally... Anyway thanks to all
 
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