Copper fittings

[noisy123]

Hi,
Anyone know why I can't thread a 1/2" MIP barb into the 1/2" copper female adapter I sweated onto some copper pipe? It starts put won't tighten easily. I assumed the 74 cent copper male adapter would be for iron pipe and not garden hose or something. The threads look right too. Is there some subtle plumber-thing I'm missing?

 

[Philip1993]

Ignoring garden hose thread (GHT), check your original packages to see if you have a NPT - Normal pipe taper (also called FPT {female} and MPT {male}) and SPT - standard/straight pipe thread mismatch. An NPT barb won't tighten well in an female SPT.

Copper threaded fittings are often SPT because faucets are usually SPT.

 

[sigmund]

Make sure that when you sweated the fitting on you didn't have solder run down into your threads.

 

[digunderground]

+1 check all of the above..

I have a 1/2" pipe to 1/2" mpt copper fitting in my MLT and the 1/2" MPT is connected to a 1/2" FPT stainless connector... works like a charm!

 

[noisy123]

Ignoring garden hose thread (GHT), check your original packages to see if you have a NPT - Normal pipe taper (also called FPT {female} and MPT {male}) and SPT - standard/straight pipe thread mismatch. An NPT barb won't tighten well in an female SPT.

Copper threaded fittings are often SPT because faucets are usually SPT.

I suspect you are right. The parts weren't labeled so they probably assume that if you know you need it, you know what you're getting.

 

[k1v1116]

when you said wont tighten well, do you mean it threads in at least 4 turns or so but wont seal? most threaded fittings need some teflon tape to seal properly.

 

[noisy123]

when you said wont tighten well, do you mean it threads in at least 4 turns or so but wont seal? most threaded fittings need some teflon tape to seal properly.

No, they won't turn.