[4]

1/4 30 tpi screws. I need to make some!

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

Machdaddy

Active Member
Registered
Joined
Jan 12, 2018
Messages
32
My single tumbler SB 9" lathe does not offer 30 tpi which is what I need. In fact I need to make about 30 of 'em for a steam engine I'm rebuilding.Can it be done? The SB 13" @ work is also single tumbler and the big Hendey, although double tumbler won't cut 30 tpi.
How would you approach this problem?
Thanks
 

craptain

H-M Supporter - Silver Member
H-M Supporter - Silver Member ($10)
Joined
Sep 21, 2017
Messages
60
It can be done. It's just a question of what gears to use. There's a formula that I don't recall for working it out. Do a Google search and you should find it. There's a couple of variables that you need to plug in. I have cut threads that were not listed on my chart.

Sent from my SM-G930T using Tapatalk
Edit: this chart might help.
 

SamI

Active Member
Registered
Joined
May 31, 2018
Messages
177
Could you not use a die to cut the threads? I guess you'd have to pick one up so not ideal if you're planning on cutting threads right away but on a batch of 30 I'd imagine it would be a big time saver.
 

benmychree

John York
H-M Supporter - Gold Member ($25)
Joined
Jun 7, 2013
Messages
3,421
A die would be way cheaper than having to buy change gears, even if in fact that they could be used on the SB setup, which is not particularly change gear friendly.
 

Machdaddy

Active Member
Registered
Joined
Jan 12, 2018
Messages
32
Sorry folks! It just never occured to me to look! I thought it was a real oddball,,,
 
[5] [7]
Top