Here is a comb I made from a piece of aluminum flat bar.
I used a hacksaw to cut the teeth and a special chisel to carve them to a rough point before using a cut strip from a sanding belt to smooth them round.

The outline was cut in using a special engraving tool that I modified from a punch.

The thumb spot was cut in using a rotary file and ground smooth using a cheap aluminum oxide grinding bit for a dremel before it stippling it with a center punch.