ASME B16.3 Thread Allowance
#1
08-05-21, 02:35 PM
ASME B16.3 Thread Engagement
Hi All,
I'm running some 1/2" and 3/4" black pipe. I need to cut and thread some very accurate sections. According to some information I dug up on how to calculate pipe lengths, I need to know the thread engagement of the fittings. I was able to find the face-to-center dimensions. So I don't need those.
Anyone know these figures off hand?
Thanks in advance!
I'm running some 1/2" and 3/4" black pipe. I need to cut and thread some very accurate sections. According to some information I dug up on how to calculate pipe lengths, I need to know the thread engagement of the fittings. I was able to find the face-to-center dimensions. So I don't need those.
Anyone know these figures off hand?
Thanks in advance!
Last edited by PaulyWally; 08-05-21 at 03:18 PM. Reason: Used wrong terminology
#2
08-05-21, 04:20 PM
Group Moderator
I need to know the thread engagement of the fittings.
Possibly an American fitting.... if you could find one.
#3
08-10-21, 10:10 AM
By the nature of how tapered threads work, there will never be a precise measurement on thread depth, since it's reliant on both the male and female cut threads.
But this should get you close:
https://www.engineeringtoolbox.com/n...ads-d_750.html
Specifically, Approximate Total thread makeup (inches)
For 1/2" pipe, the thread should seat 7/16"
For 3/4" pipe, the thread should seat 1/2"
If this is for a plumbing/gas installation, you're probably laying something out less than optimally to require a precise cut.
But this should get you close:
https://www.engineeringtoolbox.com/n...ads-d_750.html
Specifically, Approximate Total thread makeup (inches)
For 1/2" pipe, the thread should seat 7/16"
For 3/4" pipe, the thread should seat 1/2"
If this is for a plumbing/gas installation, you're probably laying something out less than optimally to require a precise cut.
#4
08-11-21, 04:47 AM
I see 6 tolerances here. 1 and 2 are the tolerances the end pieces the new pipe will connect to. 3 is the tolerance of the thread die to cut the threads in the new pipe. 4 and 5 are the tolerance of the OD and ID of the new pipe. 6 is the tolerance on the torque the connections are tightened to. I think fitting by trial is much easier than coming up with measurements for a tolerance calculation. Good luck.
PJmax
voted this post useful.
#5
08-11-21, 10:08 PM
Group Moderator
I think fitting by trial is much easier than coming up with measurements for a tolerance calculation.
