How do I keep strings from slipping at the tuning post?

A slipping string usually goes flat a little at a time, even after it should have settled. The fix is friction at the post.

How to make a locking wrap:

1. Thread the string through the post hole with the slack you need.
2. Pull the free end back around the post, toward the inside of the headstock.
3. Tuck the free end under the main string and bend it up, so the main string crosses over it.
4. Hold the string straight with a light pull and start winding. The first wrap traps the free end.
5. Let the remaining wraps stack downward on the post.

Other things that stop slipping:

• A sharp bend: kink the string hard where it exits the post hole before winding.
• Enough wraps: plain strings need more wraps than wound strings.
• Keep a light pull on the string while winding: loose wraps can tighten later and lower the pitch.
• Settle the strings: gently lift each string along its length, retune and repeat.

If a string still drifts flat after it settles, check the tuner itself. A worn gear or a loose tuner nut can let a string slip even when the wraps are good.