Everything you wanted to know about how to shim a guitar neck

Where should a shim be installed?

If using a full-size wedge shaped shim like one of these from StewMac, all you have to do is lay the shim down in the neck pocket with the thin side facing the headstock and the thicker side facing the body. Done and done.

If installing a shim using another material to save some money, you can basically use anything you want, but some materials work better than others.

Recommended materials for homemade shims and where to place them in the neck pocket

The materials I mention here will be specifically to create a wedge shape similar to the StewMac shims mentioned above.

Wedges are agreed upon by luthiers and techs to be the best way to go about shimming a neck for two reasons. First, to avoid neck damage. Second, to prevent weird noises (as in rattling) from happening during play.

Creating a wedge

The goal here is to make a wedge the same as the StewMac one, meaning the raised end facing the body and the lower end facing the headstock.

The easiest materials to work with for creating a wedge are masking tape or aluminum foil.

Either of these materials are easy to source, easy to cut, easy to shape, and most importantly easy to layer to create that "ramp" you're looking for to get the wedge shape.

Luthiers and techs won't tell you to use tape or foil but rather wood and wood alone. However this is on the assumption you have a belt sander, all the proper sanding paper at the ready, a fully equipped work area, and expert knowledge on even how to use a belt sander properly.

Using foil or tape is more than good enough to create your wedge shim with. No wood required. No belt sander required. No expensive work area required. Use what works and just get on with life.

Published 2020 Feb 27