At one time these were made in Germany. I’m not certain about the current place of manufacture.
You need masonry drill bits for ceramics
It’s about half centimeter. On the big ones
Fourteen bits from 1/16 through 1/2"
I have not needed to sharpen them as yet, but I believe you should be able to in a drill bit sharpener tool.
2 - 1/16; 5/64; 3/32; 7/64; 2 - 1/8; 9/64; 5/32; 3/16; 1/4; 5/16; 3/8; 1/2
I have used them on stainless many times and had no problems as long as I kept the drill rpm's very low and let the bit do the cutting.
I would use hardened drill bits for "hammer" drilling; they are made 3 - 5 times harder than regular hi speed drill bits to absorb the hammer impacts.
Yes. It has a reduced diameter shaftto fit a 3/8 chuck.