Will this mark or damage the center part being punched out?

It will leave a mark in the center of the punched out piece. However, you can remove the handle covering and there is an allen screw that can be tightened to prevent the center punch from moving. This can hold the center punch fully extended or retracted (by pushing in the center punch and tightening the screw). This will not allow the center punch to touch the material unless the material is thicker than the distance to the center punch.

Nothing in my kit indicates a country of origin. Nevertheless, even if they are made in , say, China, they do seem to be well made and they've worked for me when I've needed them. The only "tip off" I can detect is that the individual cutting head holder spots molded into the case list English sizes first and metric sizes parenthetically. You can take that to mean whatever you want.

Perhaps I missed it somewhere, but . . . what are the hole sizes this set will punch?

Hello and thank you for your question. The set will punch holes of the following sizes: 3/16", 1/4", 5/16", 3/8", 7/16", 1/2",5/8", 3/4". 7/8", 1", 1 1/8", 1 1/4", 1 3/8". Sincerely yours, Customer Service Team, POWHILL

Could this be used to punch-out the center of a bottle cap?

Without using my set to try it (lol) I'm pretty sure it could do it. I'm very impressed with the quality of this tool. However, if you are planning on punching hundreds of bottle caps it will get dull pretty quick. If I were to attempt hundreds of caps I would make a jig that allows the cap to sit down inside a hole that you have filed notches around the top rim to match the the cap flutes (this will prevent the cap from rotating) and drill the hole