Arched Plate Carving, Part Two: Graduating the Top Plate and Cutting the f-Holes

by Chris Burt

Originally published in American Lutherie #85, 2006

See also,
Measuring Archtop Musical Instruments by Chris Burt
Arched Plate Carving, Part One by Chris Burt
Arched Plate Carving, Part Three by Chris Burt


This is the third article in this series, which takes you from measuring worthy instruments to carving plates in the image of the instruments of your dreams. To date you’ve measured one or more fine instruments and have carved a couple of plates that require final graduation. The thickness maps you’ve recorded when measuring instruments will tell you nothing about tap tones, but they will provide a view into at least one graduation scheme that works and a general goal towards which to work.

So, how do you decide when you’ve finished graduating a plate? I can only describe my method. But heck, it’s a method based on both tradition and science. Some prefer tradition, some prefer science, some follow their imagination. I like the first two with a little of the third thrown in for fun.

The techniques I describe in this article are based on more than faith. I learned them from teachers more knowledgeable than I. I also learned them through study, insight, and refinement gained through practice. Also, I once deviated from these techniques to build a viola graduated strictly by thickness. The wood I used turned out to be less stiff than any I’d previously used. The resulting plates were not stiff enough. The mode 2 tap tone for the top was down around C and C♯. I didn’t like the viola’s sound and never tried to sell it. I should have kept the plates thicker. I’ve since accepted that each piece of wood is unique and varies from other pieces in both density and stiffness.