I have read a couple places about the Bowling Ball engraver’s platform. If you have access to old issues of Muzzle Blasts ( a National Muzzleloading Association Publication) from the 1960’s or 1970’s there was a article on how to implement a bowling ball and roller skate lock for an engraving block. If you can’t find the issue don’t let that stop you from building one. Cut a bowling ball in half ( a real fun project in itself) glue a “2 by 10” on the face (saw trim the over hang if it bothers you), mount a 2 ½’ inch machine vice (or 4 inch if your going big) to the “2 by 10.” Cut a round hole in another chunk of “2 by 10” - try about a 6 inch diameter hole. Trim the top edge of the hole with leather or rubber to help stabilize the ball from slippage. Stick the cut ball, the round part in the 6 inch hole. Go from here . . . Costs $3 for a bowling ball at a second hand store, $10 for vice at local China made tool store, 2 by 10 wood section $10 if hard pressed at local lumber yard, $2-5 glue- depending on your preference. There’s more modifications one can do but this info should be enough to get you in trouble/started.
