Sizing of Shower Nipples

[John F ATL]

I am tring to change some plumbing fixtures in a shower with a finished wall. The fixture calls for a nipple recessed 3/8" behind the finished wall. My problem is that a 2" tube is too long and a 1 1/2" is too short. What are my options? Since the threads on the nipple are tapered, a wasn't sure if I could just trim some off.

Thanks for your help,

John

[Terry]

Pipe nipples come in 1/2" increments, not making life easy.

There is a certain amount of "play" as far as how tight or loose you can tighten these things.
You can also use more thread sealant or less.
Sometimes the valve in the wall can be moved.

In some cases, there is a flange that will slide back and forth too.

[Dave Meers]

You could take a short piece of half inch copper and sweat a threaded adapter on each end to make the nipple the exact length you need. I've done that on tub spouts before and it should work for a shower nipple as well.

[John F ATL]

I thought of what you guys had suggested, but with the wall finished and a very expensive fixture and was a little hesitant about tightening too much. I used two 1/2" to 3/8" fittings with a close 3/8" nipple, tightened as tight as I could with two crescent wrenches. It was exactly 1 3/4", all for about $5.00. I hope this helps someone else.

[hj]

Depending on what the nipple was connecting, that 3/8xclose nipple could induce back pressure.