Both the MC and the fittings are from The US. The fitting threads are correct.
I solved the problem this way:
First I removed the fitting and measured the depth of the hole in the MC and compared this with the threaded area on the fitting. It was very close, but the the fitting was app 2 millimeters (1/13 inch) too short.
I filled the hole with some thin plastic to make sure no dirt could enter and carefully drilled with a large drill a app 1/13" inch down.
The drill was larger than the outer diameter of the fitting. Then I could screw the fitting a little more in and I can clearly see a couple of un-engaged thread rounds. I also feel the fitting hits the flare in the bottom.
No threads in the MC hole was destroyed. I just widened/sunk the part of the hole above the threads.
Last edited by staleg; 03-30-2011 at 02:24 PM.