One of the most common problems a string player encounters is difficulty using the pegs. It could be the humidity, structural issues, or the wear and tear that comes with time. Regardless, slipping pegs create persistent tuning problems that interrupt a practice session or performance. Understanding why these parts fail is the first step toward a problem-free instrument.

Causes of slipping pegs

While it may seem like your instrument is just being temperamental, peg failure is actually rooted in physics. Here's why.

Firstly, wood is hygroscopic, meaning it absorbs moisture from the air. When humidity drops or there's dry weather (winter or air-conditioned environments), the peg wood shrinks. Even microscopic changes can cause the peg to lose its grip and slip.

The second issue is worn pegs. Over years of use, the friction required to tune your instrument wears down the wood. This can create "flat spots" or oval-shaped pegs that no longer make uniform contact with the pegbox holes.

And if a peg has been forced in the pegbox hole for years, the friction creates a hard, glassy surface (glazing) on the wood. This surface has almost no grip, so the peg slips regardless of how hard you push it in.

Finally, the peg must be tapered perfectly to the pegbox hole. If the angles don't match, the peg only makes contact at one end of the hole. This poor fit creates a pivot point instead of uniform friction, leading to slipping or "winding" where the peg bends under string tension.

Simple fixes

Traditional friction pegs work well when installed and maintained properly. To keep your pegs in shape, try applying a small amount of peg compound during your routine string changes. This allows the pegs to turn smoothly while remaining locked in place when pushed home.

However, this only works when the pegs fit in the first place. To check the fit:

  1. Remove one string.
  2. Slide the peg out and inspect it under a bright light.
  3. Look for two continuous "shiny bands" around the circumference. This is where the peg makes contact with the pegbox and where you apply the compound.

If these bands are broken or uneven, the peg is not making full contact and will continue to slip. To assess the friction:

  1. Push the peg back into the hole.
  2. Turn it rapidly.
  3. Remove it and touch the bands to your upper lip.

The bands should feel warm. If they do, your peg fits well and you can apply a light layer of compound and reinstall the string.

Professional help

Applying peg compound can be a delicate process. If you're unsure how to proceed, your pegs are severely worn, or the wood has warped, getting an adjustment from a luthier is your best choice. A professional can adjust or replace new pegs for the perfect taper, plus recommend the right humidity control.

Whether you need a simple adjustment, professional application, or a full setup, Johnson String Instrument is here to help. We combine decades of craftsmanship with a passion for performance to keep your violin sounding its best.