Anyone know the dimensions for the screws used for the ballast and terminal block on a M400?

See if 10-32 screws, 1/2" to 3/4" long will fit.

Nope, the thread is wayyyyyyy to fine. I spent 20 minutes at Menards trying to work it out with the guy and we couldn’t find it.

Hmm I figured my M250 would have used the same screws. I'm surprised it didn't fit in the gauge, it might have been 10-24. I doubt it was a metric size like M4 or M5 since metric hardware isn't common for American streetlights and M4 and M5 have finer threads.