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Posted By: evad73 ridgid 0-r pipe threader - 08/31/10 10:37 PM
I have a ridgid 0-r hand pipe threader. I don't ever remember replacing the dies. The teeth finally broke and need to be replaced. I went to the local plumbing supply house and ordered new dies, then I thought, aren't plumbers threads different than electrical. Is it necessary to use npsm dies or npt dies? HELP
Posted By: wire_twister Re: ridgid 0-r pipe threader - 09/01/10 12:57 AM
NPT dies are fine for electrical applications, just cut the threads deep enough so the coupling or fitting bottoms on the pipe, looking for max thread engagement not pressure sealing ability.
Posted By: resqcapt19 Re: ridgid 0-r pipe threader - 09/01/10 01:14 AM
Not only are NPT dies fine, they are required by 344.28.
Posted By: evad73 Re: ridgid 0-r pipe threader - 09/01/10 02:17 PM
Thanks, this forum really helps....
Posted By: renosteinke Re: ridgid 0-r pipe threader - 09/01/10 03:37 PM
There's a little more to this than meets the die ... laugh

In nearly every 'ordinary' instance, electricians use ordinary 'plumbers' NPT dies.

However, when you are dealing with an established name like Rigid, or doing some specialty work, it's easy to get the wrong replacement inserts. Plus, the inserts are brand specific.

The best bet is to take the old inserts to a plumbing supply house and have them select the proper replacements.

Without getting too bogged down in the specifics, there are other thread patterns that also comply with "npt" (they simply have tighter tolerances); inserts with extra throat clearanc (for coated pipe), and inserts with different cutting edge profiles (for cutting different materials). There are also some oddball applications where a different threadform altogether is required - but that situation probably doesn't apply here.
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