Introducing…The Gramil (not Gremlin, but you still shouldn’t use it after midnight)
A gramil is a tool that has been used by luthiers since the time of Stradivari (his is still housed in the Stradivari museum in Cremona, Italy). It is used for cutting the purfling edge and/or the binding line. Using the gramil first cuts the soft wood fibers, preventing splits or chips that can occur when going back with a chisel or router. It’s also great for cutting lines on the hardwood back and sides.
Although the two tools are similar, a gramil is more versatile than a purfling cutter, as it can also be used to cut binding. Some luthiers have both tools and may decide to use one of the other, depending on the task at hand.
Unlike a marking gauge, a gramil will actually cut (instead of simply scribing) a line.
There are many models of gramils on the market available to purchase, although they can be expensive. Mine, which I made myself (based on a design by Richard Schneider), is flat on one side and radius on the other. The radius allows me to cut in the tight waist areas with greater precision than the flat side.
Check out my video demonstrating how to make your own gramil cutter for less than $15 in hardware.