I am restoring a vintage car and have a bit of a problem with a thread I have not come across before. The headlamps are fixed to bars that are screwed into a steel frame that surrounds and supports the radiator. It would appear that the thread is 7/8" x 16 tpi which seems from investigation to be perhaps a conduit thread. I wonder if anyone can confirm this. I have been able to find a conduit tap of that configuration but not a die. I have found a 7/8" UNS die and wonder if this would be a close fit. The connection does not need to be perfect and is as much as anything a locator as the bar is also clamped into the wing stanchion. Anything would be a help.