Neck Adjustments & Shimming

The regular folk here are familiar with my recent acquisition, a Spectrum SX, which had a magnificently high action and few other miscellaneous problems: INITIAL TEAR DOWN

It occurred to me that those unfamiliar with the subject may have been puzzled by the shimming location I used to correct the action problem and why it works. After all it isn't that intuitive a thing to do, but once you understand it, it starts to make sense.

I thought it might be helpful to start a thread on the subject of neck adjustments generally, and shimming in particular. To that end I came across a very good pictorial summary of some common neck problems and how to remedy them. The third illustration details the solution that I used:



So? What kind of hell have you had to go through? Chime in with your problems and more important, your solutions.

On many low to mid acoustics, the nut is not slotted deep enough and there may be shims under the bridge saddle.
In most cases the slots can be run deeper (and helps to have a radius gage to make them uniform to the fretboard and saddle) and shims can be removed from the saddle. Just be careful not to slot the nut too deep, or there will be fretbuzz.

You all should have bought Strats....got neck tilt adjustments. Easy peasy lemon squeezy!

IanO wrote:You all should have bought Strats....got neck tilt adjustments. Easy peasy lemon squeezy!

sarcaster wrote:On many low to mid acoustics, the nut is not slotted deep enough...Just be careful not to slot the nut too deep, or there will be fretbuzz.

Technically speaking the strings should not be "buried" in the nut slots at all. Rather, they should, ideally, "rest" on top of the slot with upwards of 50% of the string's diameter sitting proud.

You're quite right that buzzing will be generated the deeper the string recedes into the slot. The remedy for that is to simply sand/file the top until the depth is reduced to the correct dimensions. And as you say, use a radius guide to ensure compatibility with the fret board.

Can anyone explain the advantages of shimming a neck vs adjusting the bridge saddles - if there is one?
Seems a little over the top, removing the neck etc when most adjustments can be made via the bridge. Of course I understand if the bridge can't be adjusted adequately - if it is a retro fit of a different type or whatever.
ta

PaulS wrote:Can anyone explain the advantages of shimming a neck vs adjusting the bridge saddles - if there is one?
Seems a little over the top, removing the neck etc when most adjustments can be made via the bridge. Of course I understand if the bridge can't be adjusted adequately - if it is a retro fit of a different type or whatever.
ta

It is usually done when the bridge saddles cannot be adjusted more. Take for example the Pantera 300's. They all seem to come with a factory shim to give the neck an angle to meet the bridge saddles better. I don't think enough can be done from the bridge side. IMO it is a cheap way to go for production - they should have made an angled pocket, or angled heel to get the correct angle if they wanted to use the same bridge.

sarcaster wrote:
It is usually done when the bridge saddles cannot be adjusted more.

That is what I thought, really. I had an argument with my brother in law the other day - he reckoned it would be his first port of call when adjusting the action of a guitar. I guess it matters not if you achieve your aim how you get there, but to dismantle an entire instrument to do a job that can be done in minutes via the bridge seems way OTT to me.

ta.

That's why you see some Floyd time bridges routed into the body - it's because the saddles would be way to high if they were mounted flush.
Always something to consider before trying to replace a bridge.

I came across this neat little article on shimming a bolt on neck.

Seemed to fit in this thread: How to Shim a Bolt-On neck

I think thats probably the most complicated shim ever made.

Yeah I kinda thought so too.
Doesn't everyone own a belt sander and a convenient chunk of thin maple? Oh, and a hole punch, and super glue?
 
But along the way he does offer some food for thought regarding full versus partial shims.
Just another approach, ya know?

The nut is the governing culprit of your action.
Get that set and away you go with the rest.

I like a few degrees of neck tilt and will shim the majority of guitars to get this. Also don't like grub screws stabbing the heal of my hand.