They're 6-32 x 1/4". Same thing just happened to me. I know this is an old thread, but I thought someone might be looking for the same thing.

 

Pretty much every fastener known to man here. JF
http://www.mcmaster.com/#

 

If your unable to find the correct Fasteners you might be able to tap and dye it for another screw size. It's not hard at all, I do it on a daily basis. Or you can use cherrymax rivets. It's I credibly easy to shoot a rivet of you have never done it before and a rivet gun can be found decently cheap at a hardware or farm store.