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

[Ludde]

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?

[jesseskinner]

@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°

[Ludde]

Thanks!