Neil, I’ve made my own mark punches. The smallest one has a size of
1.5 to 1 mm and contains HMJ. I have etched the signature mirror wise
on some punches by the following way:
Buy some steel (HSS) or other good industrial punches. Good ones last
a lifetime and can also be used in titanium. Grind on top the size of
the mark you want to have. Polish that area and degrease the tip. Take
etching-ground or for small punches a waterproof felt pen and color
the punch tip. Scratch in with a sharp pin and steady hand your wanted
mark (it takes some practice especially on small ones) Now etch the tip
in for example the following solution
in weight parts 7 water
3 sulfuric acid
1 nitric acid
Always add the acid in to the water and keep your safety measures
You have experience with the time of etching, because this depends on
the concentration of acid and the quality of the steel you are using.
Normally it takes only 3-15 minutes. If, after etching, the grooves are
not nice , dilute your etch solution with some water and try again.
Some extra questions?