Violin Maker's Corner

Fundamental Friction Facts for Fiddler Folks

- R. J. Storm

Greg V. sent over a nifty communication asking: "Could you discuss the topic of slipping and sticking tuning pegs? When should peg hole bushings be considered? What is involved in doing this?" All good questions, so let us begin.

Classical violin pegs are simple affairs that are essentially a tapered shaft fit into a matched tapered hole. Pressing the peg into the taper should tighten things up, while a peg backing out will loosen. Easy to understand this. An absolute foundation to this simple arrangement working properly assumes a proper fit and mutual concentricity of the peg and the peg hole. The matching taper needs to have as much matched surface area as possible. Slight aberrations can occur, but wood has a certain "plastic deformation" to it and will squeeze and bend, and thus adapt to anything in the ballpark of acceptable work. When you examine a well-fit peg, it is easy to notice the tell-tale double rings that are shiny on the peg shaft. But wait, there's more. Much more. Rotation of wood on wood works so much better with a light layer of compound between the mating surfaces. Pegs need to rotate smoothly around every degree...not just a few. For this reason we can begin by diagnosing the problem in large brushstrokes.