I'm trying to find the proper mounting screws for this ST 86 movement. It's bolted down to a 5/8" mounting seat by the two screws shown here, (missing) in the bottom of the clock frame.

So, How do I determine the proper size and where can I find a pair of screws?

timesevers

Thanks Peter, I considered that, but they don't specify what size you're getting.
So.. I went to Automotive Fasteners and found them and discovered that the thread size is 6-40. That was half the battle.