UNJC Threads into a UNC Tapped Hole 1

[mullins]

I have a drawing call out from the 1960s from a certain government agency which calls out a UNJC Stud and Self Locking Bolt, however the hole call out is for a UNC-3B Tapping.

I am trying to assemble a list of Engineering Change Orders and I was wondering if anyone here had experience with the UNJC Thread Series who might be able to answer my question.

C



Taking the science out of rocket science...One step at a time.

 

[ewh]

The J signifies a special thread root profile. If I remember correctly, your drawing callout is correct; a UNJC stud can go into a UNC hole, but not the other way around. I'm sure someone will point out if I have that backward.

 

[KENAT]

http://www.tcnj.edu/~rgraham/barrett/manual1-B.html

Any help?

KENAT, probably the least qualified checker you'll ever meet...

 

[ewh]

Handy guide there, KENAT!
I didn't see where it answered the question, though. In a previous life as a designer at a world-class electro-hydraulic servovalve manufacturer, we often used hydraulic fittings with a UNJ thread, but we would not specify UNJ on the mating hole. as it was determined that the female UNC thread would clear the root of the stud thread, and performance wasn't supposed to be effected. I have never heard of the practice causing any problems, and am interested in learning if this was indeed acceptable or just poor practice.

 

[mullins]

Thanks for the responses. As far as I can tell, the UNJC stud should fit into the UNC Hole. If it doesn't I will defiantly post results on here.

Taking the science out of rocket science...One step at a time.

 

[KENAT]

Well I don't know if you need to be defiant about it ;-) but it would be interesting to have verified.

KENAT, probably the least qualified checker you'll ever meet...