I once wanted to put some lettering round a circle and did it on my lathe. Having turned the ring, in my case brass, I left it centred in the lathe and used letter punches guided by the slot in a quick change tool holder. The punches were held against the back of the slot by hand, and the clamp screws just brought down to lightly hold the punches down. The tool holder has to be squared to the work of course, and the punch payed on its side, adjusted to be at centre height. An indexing device was used to control the rotation between letters. A few experiments were needed to determine the amount to turn the work between letters. The gap varies depending on which letters are adjacent. A bonus was that I found it possible to give the punches an accurate second tap if needed. This was a one off job. If I was doing a lot, I think I would make some sort of sprung guides to hold the punches back and down in the tool holder slot. I the work is thin, then I think I would back it with some softish metal while punching, probably aluminium.