Guitar neck shim placement-bridge side of neck pocket

Problem With My Guitar Neck?

Q:  Is there a problem with my neck pocket I see something in there?

A: No problem there. It’s a guitar neck shim often used by Haywire, Luthiers and techs for years.

It is necessary in achieving very low guitar finger board action. It’s part of the correct process in guitar building, setups or perfect neck matching and alignment.

 More Guitar Education specifically….

What are the purpose of guitar neck shims?

They help guitar neck angle match perfect to the guitar. A guitar neck shim when referring to guitar builds is for a thin spacer with specific measurement particular to one guitar only. A shim for one guitar is not interchangeable with another guitar.

Terminology

The standard terminology used by luthiers for a thin wedge under a bolt-on neck is a shim.

What is the purpose of a guitar neck shim?

To adjust the angle or pitch of the neck.

Why would you need to adjust the angle or pitch of the neck?

Let’s say you replace the neck on your guitar. You install it, level the frets, re-crown, set the neck on all 4 axis, then add the two “E” strings clamp it, adjust your truss rod for proper bow, and then if notice that the height of the strings is high. You also notice that no matter how low you adjust the saddles, the strings are still sitting way too high above the frets. It’s at that point you need guitar shims to change the neck  angle so you can adjust strings to your desired string height. Now, it’s time measure for a shim. It’s like visiting a tailor for a final fitting.

Shim Placement

Where are guitar neck shims placed?

Under the heel of a bolt-on neck at the bottom or at the edge of the neck pocket. They’re called a reverse guitar neck shims at the other end of the pocket.

What can be used as guitar neck shims material?

There’s a long list of materials that could be used. You could use a guitar pick, a thin piece of veneer, a business card,  a thin sheet of metal, however: HVAC silver sealing tape is one of the best choices. It is preferable to use a material that can but cut to fit across the width of the neck easily, and/or layered and won’t degrade with age. Shims are also sold by Fender and Stewart-MacDonald.

Is it always required to use guitar neck shims whenever fitting a new bolt-on neck?

No. If after installing the neck and adjusting the truss rod you see

better action possible and you can set your action with string height better then use a shim.

You will need one, because the likelihood of a new bolt-on neck fitting exactly right just doesn’t happen. It’s up to us to “make it happen”.

Why are  guitar neck shims needed for new neck installations?

Because wood is unpredictable in how it will settle in once installed. No two necks fit exactly the same on a body. As long as the bolt-on neck is installed properly and has a  good, snug fit, the guitar neck shims do not affect sound whatsoever. Is it true some builders purposely put in a shim gap for tonal purposes?

As a result, some builders do believe that the gap created by a shim actually adds a certain tonal quality and keeps the angle correct all in one operation.

If you’d like to learn more about guitar neck shims and the guitar building process just go to HaywireCustomGuitars.com and click on BLOG for over 100 articles here:

Rick Mariner-Haywire Custom Guitars, Custom Shop

Guitar neck shims help guitar neck angle be perfect