The Workbench

Neck Shimming A Bolt On Neck


On my Mosrite Avenger I took the neck off to find two picks and a couple washers between the neck pocket and the neck, actually the picks were probably laying on the neck pocket and the washers were embedded into the neck end. This was much to my surprise then I realized a previous owner had the neck shimmed.

I know a friend of mine bought a Jazzmaster brand new made in Mexico and he took the neck off to see a playing card as a shim. He was mad because he felt for that kind of money they could’ve used a proper shim that would have been made for the purpose of a shim rather than a playing card.

So I did some research and many believe that you should use a full neck pocket shim because if you just put something at the end of the neck it’ll cause the neck to sag eventually but some people actually don’t believe that from when I read what do you guys think?

You can buy full neck pocket shims from Stew Mac. The problem with that is shipping is probably about eight dollars and the shim is probably about eight dollars so you’re paying over $15 for something that might not be the right angle and then you’re going to have to buy another one after that because you’ve already probably marred it and can’t return it if it doesn’t work. And it looks like it’s a difficult task to make one out of wood because you have to angle it right and all that stuff. Some people use business cards and kind a layer them but I think you and that’s hard to get the right angle.


I think the ladies who used to assemble Fender guitars back in the pre-CBS days used to use cut up cigarette packets - it's not a new thing.


Here’s a picture. By the way I think that the right neck angle was set pretty good with the picks but that neck sag issue concerns me about using the picks and washers rather than a full neck shim.


One pic from the picture as you see I had the pick stuck on the neck I guess from pressure but it came off easily. Another one was laying on the neck pocket.

It had moved over of the bolt hole for the neck. Obviously it was not there when it was in the neck or It would not have gone through.

Thanks in advance for everyone’s help.


D'Andrea make great picks, and you got two free!

You could try construction shim stock, like they sell at Home Depot, Lowes, or other hardware stores.

But I wouldn't worry a lot about sag. If it really concerns you, you could stack cut playing cards higher at the butt end, and make increasingly smaller stacks toward the headstock end, so that you support the heel block in several locations.


Get a roll of 1" hardwood veneer at Home Depot.


And in this game, consonants are free. Please fix "simming" in the thread heading.

I didn't know if we were going to talk about slimming, slumming, summing, shimming, shunning, simmering, or shimmering.


And in this game, consonants are free. Please fix "simming" in the thread heading.

I didn't know if we were going to talk about slimming, slumming, summing, shimming, shunning, simmering, or shimmering.

– Proteus

...or swimming.


I think a full pocket shim is worthwhile except fo the occasional situation where one side needs to be angled up a little bit. PIcks do not shims make (!)


Don't worry or over think it too much. Folks have been doing this since way back and the idea is that you raise the bridge a little to deal with the back slope of the neck. There's theoretically an increase in sustain and tone from a greater pressure on the bridge


Yes, please make or have someone make a decent shim. It will sound better and it's better for the guitar.
I got a whole lot of maple veneer and wasn't expensive. It came as a huge sheet so I think I'll be able to shim guitars for the rest of my life and long after that...


Personally, I've shimmed plenty of guitar necks with sliced up business cards and cut sections of picks. Usually I try to keep the shim size to the space between the end of the neck pocket and the closed two mounting screws. The only guitar where I didn't use that technique was when I installed a B16 on my Tele, had to use the Bigsby shim for that.

I'm sure a full size shim is better for vibrational transfer, but any difference is lost in the equation of other factors, in my case being primarily my playing skill.

I haven't seen that many shims in Mosrites because usually the heel has a few degrees of angle built in. May not be the case with Avengers, as I haven't inspected any of those in person.


Danman how did you angle the shim? I mean shape into a wedge where it’s thicker toward the end of the neck and thinner at the opposite end? Thanks.


Thanks everyone for all your suggestions. Saw some great material for a shim at Home Depot and at a wood working shop like Billy and Proteus suggested. I have to figure out how to shape it. Block sander? Planer?

So for now I put it back as it came.

Reason I did this was because I was changing the pickups from stock Mosrite Japan pickups to Ed Elliot pickups I’ve had for years. The two neck screws right under the pickups were too long and hit the bottom of the neck pickup. Apparently the stock pickups are a bit more shallow than the Elliot pickups. I had to change the bolts to shorter ones. I should have maybe just left the neck on and replaced the two without taking the whole neck off. I’m sure those long bolts were added later for some reason and not stock. The ones I installed are perfect. Not too long but long enough to go all the way to the neck pocket and not beyond. The bolts I replaced must have been very long because they have been cut, probably by a Dremel.

Turns out I prefer the stock Japanese Mosrite pickups better. I’ll used the Elliots for now but later change the pickups back to the originals.

I have no idea which should more Mosrite as I’ve only tried a Mosrite Mark 1 twice. I have a Mark V but the pickups are smooth top which are different.


This is a classic example of a little bit of knowledge being a dangerous thing,


TK Smith makes a PERFECT alum shim.

– TheNocturneBrain

the tk aluminum shim is a beautiful piece of all his stuff is..but it's for a particular use...adding a bigsby to a tele...

shims depend on just what's going on at the guitars body/neck joint...sometimes full pocket shims are needed...other times shims towards the body side are needed, and sometimes shims towards the neck side are needed...totally depends on the problem!!..there is no 1 cure all

funny thing is fender 70's had 3 bolt necks with tilt adjuster..and everyone complained they were tone suckers..but, they were actually quite clever

also danelectro used tilt adjustments to good effect about a decade before!!!

lastly, i have seen the neck hump problem with some shims...why a wood or paper based shim is a good idea..materials that have some affinity with the guitar wood its shimming!



This guy is good. Checkout his step by step process on how to make a neck shim -


Danman how did you angle the shim? I mean shape into a wedge where it’s thicker toward the end of the neck and thinner at the opposite end? Thanks.

– ThePolecats

Hi Polecats,
I do it in a different way than the guy in the video. And my way I feel I have much more control over the angle and thickness.
It's hard to explain. I'll see if I can make a drawing or take a few pictures later. It's not that hard but you just have to get the angle right and it has to be flat.


Danman, thanks. Look forward to your pictures later.


I thoroughly enjoyed the Crimson Guitars video. Classic British dry humor!


I use a selection of various thicknesses of hardwood veneers originally intended for furniture refinishing, and sand the shim on a piece of 220 grit sandpaper on a flat surface to create the angle I need. It's easily done, with a bit of trial and error initially, and I've always found that the full-pocket shims provide the best solution.

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