Polymer Thread

[thepieman]

Im designing a piece of equipment with the need for a plastic thread. The diamater is approx 90mm

This thread will not be load bearing or need to be tightened much, just needs to do up loosely and sit there. It will also be done up and undone often.

I was thinking of a thread similar to that on pvc plumbing pipe which seems pretty rugged and tough and doesnt require many turns to do up but i cant find any information at all on it.

Does anyone know anywhere where i can find specs on this thread or a thread that would do something similar, or should i just design a thread myself?

Thanks in advance

 

[patprimmer]

Did you try google.

Did you try the major plastics raw materials suppliers. I do know many have published design details for threads. Certainly BASF, Ticona, DuPont and DSM have.

Regards
Pat
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[thepieman]

Thanks for that, just what i needed.

Did search google, but came up drawing blanks, didnt think of looking at the manufacturers so thats why i came here.

 

[MikeHalloran]

PVC plumbing pipe uses, guess what, pipe threads.
You should find details in your Machinery's Handbook.

However, pipe threads are not optimized for plastics, and especially not for repeated makeup.

You might look at stub Acme threads, or any of the fire hose threads, or Camlok couplings.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

A thread optimised for plastic is VERY different to a thread optimised for metal, the major reason being the increased notch sensitivity of plastics.

Regards
Pat
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[thepieman]

I understand pvc pipe uses pipe threads, but it isnt a standard thread and i cant find the details of it, and it is these details which i was after. As you say a plastic thread is very different to a metal one, hence trying to find plastic specific designs so that i cant get it right.

My problem is compounded due to that i want a large pitch but can only have a small thread depth due to dimensional restraints, so a non-standard design is required. I was looking for help in speccing a thread like this.

 

[patprimmer]

Did you see my first reply. Data is available, but I have better things to do than search for you and post links.

Regards
Pat
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