Here is a tool not so common, originally designed for instrument making, but that can also be used for any kind of precise woodworking.
This tool goes back to the golden age of violin making in Cremona, and could be found in Stradivari’s shop. It is very accurate, far better than the common way used nowadays which is to use the drill press …
It is a punch with a hardened steel point, that is intended to be used after
roughing out, to mark the wood to the desired thickness, in order to guide the
planing and scraping to final thickness.
When the marks disappear, you are at the good thickness.
My version has some personal touches :
Some brass and ebony turned knobs.
A flat “anvil” base 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.
On the handle side, I have added a couple of steel stops, with a rounded face, it gives a clear “clap” when you reach the desired depth, and you don’t have it if the wood is too thick.
This knob is a lock nut that stops the needle in position. The brass part goes through the ebony and is tapped. It is pinned in the wood.
The thickness gauge is used to setup the depth of the needle. (see this article)
An example of the marks it leaves on the wood.