Making a Permanent Shim for Saddles & Nuts - Tutorial with Subtitles

Chapters
0:00 Removing the Saddle (or Nut)
2:04 Removing the Bridge Pins with Blunt Fret Cutter
2:41 Backing Plate, Wax Paper, Shim Material, Superglue
3:43 Glue Caddy
4:18 Nuts with Radiused Bottoms
5:27 Trimming the Shim the Hard Way
6:10 Trimming the Shim the Easy Way
8:09 Chisel or File Cleanup
9:29 Nut and Saddle Sander - Get the Bottom Flush
9:47 Sanding Nuts with Radiused Bottoms

How to make a permanent shim for an acoustic guitar saddle or nut for any stringed instrument. Temporary shims can work OK, but permanently bonding a shim to the bottom of a nut or saddle yields more professional results, not the least of which may be enhanced tone, sustain, and projection, from having solid contact instead of air gaps. Mechanical impedance is a thing, and the more solid, gapless contact you have between all the vibrating parts of a guitar, the better.

I prefer wood veneer, though any material that's hard enough will work. Mahogany veneer seems to take CA glue very well. I've also used cherry and maple.

If you accidentally remove too much from a saddle, or even a nut, this is a fantastic save. It's a solid and effective repair for nuts and saddles that are too low. Typically, for me, filling nut slots with Nut Rescue Powder (or baking soda) and superglue is my go-to method, but for raising the entire nut at once, or correcting a nut that has the problem of the strings not sitting deeply enough in the slots and being too low, a shim is the way to go, unless you want to replace the nut entirely.

Make sure you clean off the teflon after using it, and it'll be good to reuse indefinitely. With a good supply of veneer or other shim stock on hand you'll be able to do this as many times as you need on any instrument.

Thin brass or aluminum could also work, for a more interesting and harder choice. Might even make a difference to the tone, projection, or sustain in an even greater way. Never tried it myself, but now I'm wondering!