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Threading A Clamping Nut Question

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Nicole6022

Aerospace
Mar 23, 2010
22
I have a clamping nut that is a part of a coaxial connector and need to know if I can thread the portion shown in the attached drawing (I didn't inlude the whole clamping nut just the area I want to apply the exterior thread too).

Basically my question is how do I determine if I have enough contact area on the outer diameter (where the wrench flats are) to create a strong mating?

Any help would be greatly appreciated.
Nicole
 
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You want to put an external thread on this?
 
Thats the idea . . . assuming its possitble . . .
 
I would (best case scenario) like to put a 1.438-18 UNEF external thread on it.
 
start by looking at your major/minor thread diameters and see where they will end up on the part. Your drawing is missing some dimensions that would be needed to provide a better answer.
 
It looks like the distance across flats is about 1.420". The minor diameter of a 1-7/16 UNEF thread is 1.3693" from Machinery's H'book. Not sure what your objective is but you either have incomplete thread engagement or crushed threads if you try to use the wrench flats for their intended purpose.

Bruce
 
Thanks Ceramicguy, I will not be using the wrench flats once the thread is machined onto the piece.
 
I think I understand your question. Standard equations allow you to calculate required thread engagement, but you have an interrupted thread. I would use the standard equations and reduce the thread area by the proportion of threaded/unthreaded area you have.
 
it is hard to tell without more dimensions but to me it "looks" like you will get full thread profile on the wrench portion and partial thread profile (the thread peaks) all the way around your part. I would highly doubt this will be equivalent in strength to a full thread but should be pretty darn close. Looks doable to me.
 
Thanks for everyones input, it was all very helpful.
 
And you are designing equipment for aeroplanes that fly with passengers?
 
I do (electrical mostly), but this paticular piece is for a different (much less critical) application.

As an FYI I took the part to a machine shop and was able to determine that there was not enough area to provide sufficient thread contact.

Everyones comments were appreciated.
 
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