Sharp Thread on bought in part

[Robms6]

Hi all,

I have a problem with a bought in part that has ultra sharp edges on the thread, 1/8-27 NPT. Does anybody have any suggestions on how to remove the sharp edge as they are causing a problem when screwing into a mating part. Filing/stoning are not an option in this case as this is a delicate pressure transducer and must have a good seal between threads.

 

[Jboggs]

Try tumbling deburr.

 

[Screwman1]

Check the thread dimensions to see if they are in print. You should not have a dead sharp crest if the pitch diameter and major are in spec.

 

[CoryPad]

NPT threads have specified minimum and maximum flats at roots and crests. For 27 threads per inch, the required minimum crest flat is 0.0020 inches, which may seem ultra sharp but meets the specification. You should have the parts measured.

 

[ornerynorsk]

Did you properly spec the thread and/or the threading process? Sharp threads sound like die cut threads that a plumbing shop would produce, not a fitting for a fine instrument.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[Robms6]

The thread is as standard on all the pressure transducers. I was going to run them through another 1/8"-27 npt die to try and take the sharp edge off. A lot of the other 1/8 NPT fittings we get do not have the sharp edges on the threads. We have spoken to the company that produces the pressure transducers but they dismiss it and say the threads are fine when they clearly aren't.

 

[jbeckhou]

Time to find a new vendor.


Petrotrim Services, LLC

http://www.petrotrim.com

 

[ctopher]

I could be a China made part. Check the supplier.

Chris, CSWA
SolidWorks 14
ctopher's home
SolidWorks Legion

 

[ornerynorsk]

Unfortunately, there are plenty of shops in the west with the ability to turn out crap, as well. We source many parts from China, and as long as specifications and accountability are clear to all parties, we experience great success.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[Compositepro]

As you suggested, just chase the threads with an appropriate threading die. And find a new vendor.

 

[Robms6]

Thank you guys for all your comments.

 

[tbuelna]

You might want to check the external pipe threads on you transducer with a standard gauge to make sure they are within spec.

Personally, I try to avoid using pipe threads for fluid systems. They do not provide reliable connections and are messy. O-ring, flared tube, or compression fittings are far more reliable.