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Guitar Neck Shims For Perfect Alignment: Haywire Custom Shop Educational Article

/, fix your guitar buzz, Guitar Action, guitar comfort modifications, guitar neck shims, Guitar Repair Education/Guitar Neck Shims For Perfect Alignment: Haywire Custom Shop Educational Article

Guitar Neck Shims For Perfect Alignment: Haywire Custom Shop Educational Article

Guitar neck shims help guitar neck angle be perfect
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 be perfect for a 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.


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 neck shims to change the 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 is needed, use a shim. You can set your action string height better and lower when you 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 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

Guitar neck shims help guitar neck angle be perfect

About the Author:

Mr. Rick Mariner Owner and Founder and CEO of Haywire Custom Guitars Inc. He is a member of The Association of Stringed Instrument Artisans (A.S.I.A.) as well as a guitar player. Rick holds a bachelors degree from University of Md. and a Masters degree from George Washington University. Rick developed his exclusive 8 – Point “Gig- Ready” guitar process that allows for Custom Guitars that are “GIG-READY”. With Rick’s many years of development and guitar set-up experience, Haywire Guitar shop “Builds satisfied players… one Haywire guitar at a time”.