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Joined
Sep 7, 2019
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Location
Germany
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
 
Thorsten,

Try here:

https://www.machiningdoctor.com/charts/unified-inch-threads-charts/
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
 
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.
 

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