While not a real plumbing issue, I'm hoping someone here can help....

I'm starting with a FIP coupling. I'm looking for a fitting, sort of a bushing or a close nipple I can add to the coupling which is also threaded inside. I want to add two pipes to the coupling, one inside the other. Sizes are up in the air at this point but I'm hoping to use 1" or 3/4" on the outside and 3/8 or so inside. I have plenty of bushings, but the hex on one end stops me from adding a pipe to the outside. Any suggestions?

FYI, it's one of my wife's hair brained ideas for a light.

Thanks

Ok, so you are making a light fixture. What is the purpose of each pipe? will it be weight bearing on the outer pipe? Inner pipe? Is the inner pipe being used as conduit? Depending on the specific need, there are possible options. If you are needing something that has both inner and outer threads, a machine shop that does custom metalwork is your best option instead of trying to mix and match with plumbing fittings; They can lathe or simply use a heavy enough walled pipe to use both a tap and die on. Since this isn't for use with plumbing, a regular pipe nipple may be able to be tapped out on the inside to accomplish this.

Remember.....Pet Rocks were a hair-brained idea. Ya never know!

I'm looking to add a bell reducer to the outer pipe to loosely insert and cover a porcelain socket. The inner pipe would serve to actually mount the socket which comes with either 1/2 or 3/8 FIP. The wires would be inside the smaller pipe. There wouldn't be much of load on the fitting.... Just the reducer and light socket... No globes. I want to make nice tight fittings.... No gluing or caulking sockets into reducers

I just tried one of these.....

[m.homedepot.com]

Inserted it into 3/4 coupling and then added 1 x 3/4 bell reducer on outside and 1/2 nipple up the middle. Worked great but I wish was a bit longer with a few more threads on the outside to grab the 1" reducer and coupling. Might work fine for just a light though



Edited 1 times.

Just wanted to offer this as a possibility. For the internal pipe that will house the light socket and contain the wires, you could use a pipe small enough to slip inside the larger pipe. In that gap between the pipes you could simply use something like kitchen twine and gorilla glue to center the pipe and fasten it to the outer pipe. The bond on something like that would be more than plenty strong. Keep in mind that you aren't plumbing, so connections don't need to be watertight, just stable