I'm in need of some sort of engraving machine for marking calibers, barrel twists, etc. I've been looking at the old style pantogragh engraving machines that use the templates. They come in all different sizes, and relatively inexpensive. I've looked at the etching style kits that use batteries and chemicals, don't want to go there. Currently I use the hammer and stamp method. This works ok, but no matter how hard I try it's never 100% perfect. Any comments on the pantograph style engraver?

I have a floor model New Hermes and am fortunate to have 8 sets of fonts. I would search all trophy shops and see if they have one in the back room. Most have updated to CNC. I have found a few that way and they were very reasonable.
Butch

I bought an inexpensive generic pantagraph from Gems on Display. Then built a table to hold it down. I made a movable V block to hold the barrels in a stable position. I ordered a set of New Hermes fonts. I have had to replace a couple of screws otherwise it has served me well.
Longshot

you can see a photo of what David Miller uses on pages 122 and 123 of Tom Turpin's book entitled Mastery of Wood and Metal.

there are some good buys on ebay on the new hermes

I have a New Hermes and it has been very usefull for engraving calibers on barrels also tools and fixtures.

I've found a few with the motor operated spindle. When doing engraving on a gun is it mandatory to use the spinning cutter or is the diamond tip scratcher all thats needed?

You can put a diamond scratcher as you call it in the motorized head.
Butch

There's also many etching ways to do this...I personally use a Cronite Engraving Machine...kinda of spendy, but there are other less expensive methods that make a very fine, neat impression