Remachining male thread new TPI

[madmachinst]

I have to convert a hiduminium recoil tube from 9/16-32 to 17/32-36. Thread pitch kinda close and not so close. can it be done?

 

[APD]

low probability of success

 

[madmachinst]

OK, so better luck hitting the female part with a 9/16-32 tap. Thanks

 

[technocrat]

You are going to lose part of some threads, then a whole thread crest and the cycle will then repeat. Going from larger to smaller on the od means you have more meat to work with. I would cad draw the two threads and then decide if I am loosing too much meat for it to be safe. It's likely to come down to how many full enough threads you have left.

 

[moonlight machine]

OK, so better luck hitting the female part with a 9/16-32 tap. Thanks

I would do a 9/16 36............

 

[john.k]

Loctite is your friend in such situations.....recut the thread ,and slop it all with red loctite.

 

[Limy Sami]

Loctite is your friend in such situations.....recut the thread ,and slop it all with red loctite.

man after my own heart - must be the Aussie blood in me.

 

[EPAIII]

Pitch 1/32=0.03125"
Sharp Vee Height = 0.03125" x 1.732 = 0.0541"
Minus 1/8 H, crest and root (x0.75) = 0.0406"
Two sides so X2 = 0.0812"
9/16" Diameter - existing thread = 0.5625" - 0.0812" = 0.4813"
And 15/32" = 0.46875"

At 17/32" = 0.53125" you are almost 1/16" short.

Aint gonna work!

 

[madmachinst]

Thanks guys. I ordered the tap to make the female part bigger and the right pitch. After EPA III's post I feel much better about ordering that tap. Male part is already 32 TPI so no sense in changing that.