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.685"-40 or 11/16-40 dimensions


Ludde
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I plan on doing some gunsmithing but have a hard time finding official threading data / dimensions anywhere on the typical bull barrel compensator thread .685"-40 or 11/16-40 tpi.

Can someone help me and guide me in the right direction or take a screenshot of the data from some official machining book?

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@Ludde

 

go to here http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx

 

Enter the class of fit, diameter and TPI and you are golden.......

 

but here is the data assuming a 2A fit:

Thread Data
       
Definition: (0.6875)-40 UN 2A
(External)
Diameters
Major diameter: 0.6863 / 0.6812
Pitch diameter: 0.6701 / 0.6663
Minor diameter: 0.6566 / 0.6487
Over wires: 0.6918 / 0.6879
Wire diameters:                      0.0140 Min0.0144 Best0.01800.0225 Max
Tolerances
Allowance: 0.0012
Major diameter: 0.0051
Pitch diameter: 0.0039
Minor diameter: 0.0078
Length of engagement: 0.6875
V-Shape
Pitch: 0.0250
Real pitch: 0.0250
Crest flat: 0.0061 / 0.0009
Crest radius max: 0.0027
Root flat: 0.0050 / 0.0031
Root radius: 0.0029 / 0.0018
Thread depth: 0.0188 / 0.0123
Flank length: 0.0217 / 0.0142
Lead angle
Major diameter: 0.67°
Pitch diameter: 0.68°
Minor diameter: 0.70°
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