UNF threads

[Thorsten Steinberg]

Hello all you there,
I want to mill UNF 5/16 20 and #10 32 on my cnc mill with a 60° thread mill. I live in Germany and am not familiar with US threads. I found values for drilling core holes, but nothing about how deep the threads are to be cut. Can anybody help?
Regards
Thorsten

 

[ShopShoe]

Thorsten,

Try here:

Unfied Threads (UNC/UNF/UNEF): Charts & Formulas

The Ulitmate Unified Inch Screw Thread Resource: Basic Dimensions, Classes, Tolerances, Formulas, Charts, and Explanations

www.machiningdoctor.com

I got that reference by Googling "UNF thread specs"

The major machining reference book in the US is "Machinery's Handbook" and there are older versions online for free that probably have the information you need. Google will find them for you as well.

I hope these references will help you and I wish you well with your project.

--ShopShoe

 

[Thorsten Steinberg]

ShopShoe,
Here you go!
thanks for your food for thought. I googled a lot before my post with no answer to my question, but I think the following link takes you to all kinds of threads with all information you need.

ThreaDoctor: Advanced Thread Calculator (UN, M, NPT)

The ThreaDoctor will calculste for you: Nominal thread data. Allowed tolerances depending on the thread class. and much more...

www.machiningdoctor.com

Best Regards
Thorsten

 

[L98fiero]

Hello all you there,
I want to mill UNF 5/16 20 and #10 32 on my cnc mill with a 60° thread mill. I live in Germany and am not familiar with US threads. I found values for drilling core holes, but nothing about how deep the threads are to be cut. Can anybody help?
Regards
Thorsten

As a general rule, the nominal diameter minus the pitch will work as the tap drill size for any 60 degree thread. It's not exact but very close to what the 'proper' calculations come up with. The nominal diameter of the #10 screw is (10 * .013) +.06 =0.19 -1/32=.159 tap drill, a 76% thread is 0.1590.