I had a Franz Huhlman engraving machine. I looked for years for a manual and never found one. So, I sold the machine. I asked for the best offer and it was gone in a day. I had originally paid $100 for the machine and lots of tooling. The first offer of $1700 got the machine and all of the stuff.
I may buy a CNC engraver. They are inexpensive, quick and so versatile.