I guessed based on the pics and length, lol.

The ones to get at Home Depot are called Crown Bolt socket cap screws M3-.5 x 20mm for the longer outside handle ones and M3-.5 x 8mm for the short one for the inside handle piece.

You can also go slightly longer and fatter incase you stripped yours out a bit... I did not luckily, but these solved my handle "creaking" with the new Uber II Nxt gimbals.