need info for thread milling...

[WRMorrison]

I'm trying something new....thread milling. I want to do a 1 3/16-16 internal thread, but I'm having trouble finding the requirements that my CAM software needs. I need to know the minor dia. (1.1875?), pitch (.0625?) and thread heigth (no clue). Can anyone steer me in the right direction?

Thanks,
-WRM

[cam1]

Hi:
Minor Diameter = Major Diameter (1.1875) - thread pitch (1/16)=1.1875-.0625
Height of thread is a variable, but in general .6134/(threads/inch) gives you a 70% thread depth.

Minor diameter is what you bore the hole to, and the thread height is what the thread mill removes in order to generate the thread.

Pull out the calculator and crunch those numbers out...

cheers

[cam1]

Oops sorry made a mistake...
For internal threads, the minor diameter is correct, the thread depth is = (Major diameter-Minor diameter)/2 .
(1.1875-(1.1875-.0625))/2

sorry, I was calciulating the depth of thread for an external thread.

[WRMorrison]

OK, so let me get this straight...

For 1 3/16-16 internal threads:
minor diameter = 1.125 (1.1875-.0625; what it's bored/drilled to before threading)
pitch = .0625
thread height = .03125 (((1.1875-(1.1875-.0625))/2)

Correct?

-WRM

[cam1]

correct!

regards

[WRMorrison]

Thanks a million, I appreciate it!

-WRM

[cam1]

My pleasure.
PS: if you have never thread milled, consider trying it on something soft like wood or blue SM, thread mills are pricey....