This is probably not due to the product, because the holes I drilled in the piano hinge were too small for the drill. The smallest drill bit in the set was too big, and it looked like there were two drill bits exactly the same size, and neither was small enough to fit the piano hinge hole. I could see how this should work fine, but it didn't work for me. Either they sent me two identical sizes (and one had to be smaller), or the two sizes were so close to the same size that it didn't matter.