Here is my latest tool, for instrument making, but can be used for any kind of precise woodworking :
It is a punch with a hardened steel point, that is intended to mark the wood, after roughing out, to the desired thickness, in order to guide the planing and scraping.
When the marks disappear, you are at the good thickness.
This tool could be found in Stradivari's shop at the golden age of violin makers and is very accurate, far better than the common way used nowadays which is to use the drill press ...
My version has some personal touches :
Some ebony turned knobs.
A flat anvil for flat pieces, like this violin side (must be calibrated to 1.1 mm)
and also a rounded one for curved surfaces like violin plates. You just need to remove the flat cap.