[Unregistered]

I need to attach two male threaded attachments to each other and both are stationary (neither one can rotate). I bought a coupler with threads, but discovered that when one side tightened, the other loosened! I went to the Hardware store and was directed to a left/right coupler, but this one is a gray metal and the things I am attaching are 1/2" copper pipe and brass from a shower control section.

Is it acceptable to use these metals together and get a good water tight seal?

 

[Grumpy]

I'm not a plumber but... Have you tried a union? I used to work at a hardware store and I know what you need exists.

A quick fix may be flexible tube and hose clamps

 

[Tanias]

I need to attach two male threaded attachments to each other and both are stationary (neither one can rotate). I bought a coupler with threads, but discovered that when one side tightened, the other loosened! I went to the Hardware store and was directed to a left/right coupler, but this one is a gray metal and the things I am attaching are 1/2" copper pipe and brass from a shower control section.

Is it acceptable to use these metals together and get a good water tight seal?

You should not attach copper directly to galvanized fittings of any kind without using a dialectic union to prevent electrolisis which can destroy both the galvanized fitting and weaken your copper. Your best bet is to go to your local plumbing supply store. Many of them sell to the public anymore. Tanias