I am replacing the original pads in my Cane Creek SCR-3 brakes, with Shimano. The Allen head in one of the original retaining screws is rounded out. Probably damaged during assembly, I've never touched them. I got the screw out with pliers, and expected to replace it with one that came with the new pads. But the threads are different... look identical to the eye, but the Shimano screw just won't go in. The pads are compatible but the screws aren't? Nobody told me that.

I guess I can put the old screw back in with the pliers, but I should get some replacement screws that will work. How do I figure out what I need? Will a shop know what to give me? Or will they have to fumble through their big box of assorted nuts and bolts?