To shim or not to shim?

mmbongo · #1 10-09-2012, 01:49 PM

I've got two similar basses, one 4 string and one 5 string. I just can't get the action low enough at the neck heel of the 4 string. The 5 is perfect. I've got the saddles all the way down on the 4 (heck they are almost all the way UP on the 5) and it's still just too high.

The truss rod is fine I think. I've got it where it needs to be. There's no buzzing to speak of, it's just not as effortless to play as its 5 string brother and I just can't get the same punchy sound out of the 4 (but the 4 is 34" while the 5 is 35").

Is a shim in order here? I'm by no means some great expert at setups but I feel I know enough to do it right. I'm not afraid to adjust the truss rod and stuff, but I've never done a shim.

Guess it wouldn't hurt anything to try it, just wanted to see if this is what I need to be looking at doing first!

electracoyote · #2 10-09-2012, 01:51 PM

Two places to look before you shim: Nut slots and fret leveling.

Andyman001 · #3 10-09-2012, 01:57 PM

Wouldn't hurt to try. I've used old "gift" cards and also some thin brass sheet. You might need to experiment with a couple different thicknesses.

mmbongo · #4 10-09-2012, 02:04 PM

Quote:

Originally Posted by electracoyote

Two places to look before you shim: Nut slots and fret leveling.

Nut slots are good. I've actually replaced the nut. Fret leveling would definitely be beyond my capabilities. It just seems that the action gets higher and higher as it goes towards the bridge. It's not like it's ungodly high, but it's the highest of any of my basses, and the saddles are slammed down...which puts very little downforce on the saddles if I string through bridge on it.

mmbongo · #5 10-09-2012, 02:04 PM

Quote:

Originally Posted by Andyman001

Wouldn't hurt to try. I've used old "gift" cards and also some thin brass sheet. You might need to experiment with a couple different thicknesses.

How thick would be too thick? Two business cards?

My logic is something like..I need this to come down a full 1mm at the last fret so should I put 1mm worth of shim in there?

Andyman001 · #6 10-09-2012, 02:24 PM

It depends on what kind of shim, full length or a strip shim. I use a strip of shim between the heel and first two screws. Two business card sounds like a good starting point.

jumbodbassman · #7 10-09-2012, 02:34 PM

i use the mesh that you use to sand sheet rock. the abrasive feel also IMO helps prevent neck shifting also. start with one peice about 1/2 inch by about 2 1/4 closest to the pickups... you will be suprised how much that little peice will effect the whole neck angle etc....

dmusic148 · #8 10-09-2012, 02:36 PM

Quote:

Originally Posted by mmbongo

How thick would be too thick? Two business cards?

My logic is something like..I need this to come down a full 1mm at the last fret so should I put 1mm worth of shim in there?

No. This is a case of 'a little goes a long way.' A slice of a business card would probably do.

Hapa · #9 10-09-2012, 02:45 PM

Quote:

Originally Posted by electracoyote

Two places to look before you shim: Nut slots and fret leveling.

umm no. removing metal from frets to lower action is just wrong. Filing the nut to lower action, when the bridge can't go any lower is just wrong.

A business card is 100% reversible and many times does the trick. To be over the top trace your heel on maple veneers and cut it out with an exacto knife. Fit to neck pocket, sand one side down to slope the angle. honesty a card works just as fine but never seems like a pro fix.

mmbongo · #10 10-09-2012, 02:46 PM

Sitting at work...can't wait to get home to try this

darkstorm · #11 10-09-2012, 02:46 PM

Since you cant lower the bridge saddles any more. A shim is the only solution.

lowendrachel · #12 10-09-2012, 02:52 PM

Don't mean to high jack your thread. But where can I buy the shims?

I have a precision that has some buzzes on the D string from 12th fret and up.

Rachel

Ewo · #13 10-09-2012, 02:54 PM

Quote:

Originally Posted by mmbongo

Sitting at work...can't wait to get home to try this

It's not a difficult thing to do, and a shim is the proper fix when the fretwork's decent, the neck relief is what you like, and the bridge saddles can't be lowered as much as you want. Just keep in mind that you're adding a narrow piece of thin material to the heel of the neck pocket, with the intent of tipping the neck back a bit.

It's surprising how much difference a very thin shim can make. Wait and see!

Ewo · #14 10-09-2012, 02:58 PM

Quote:

Originally Posted by lowendrachel

Don't mean to high jack your thread. But where can I buy the shims?

I have a precision that has some buzzes on the D string from 12th fret and up.

Rachel

No need to buy shims. A 3/8" wide strip of business card works fine.

But a shim isn't to fix buzzing, anywhere on the neck. Actually, it's the opposite: to allow you to lower the action more than it already is, when the bridge saddles are as low as they can be adjusted.

From your description, sounds like there's a bit too much relief in the neck, and the D string bridge is bit low.

Bobster · #15 10-09-2012, 03:04 PM

mmbongo,

What type of bridge plate is on the bass? Is it a thicker or thin one?

If it's a thicker plate (anything bigger than 1/16") I would definitely recommend trying out a shim. Start with a strip the width of the pocket and about 1/4" wide at the rear edge. Work up from there.

Best of luck

Bob

Carver · #16 10-09-2012, 03:06 PM

I use Post-it notes...Cut off and use the top sticky section... you can add/remove layers to dial it in. Easy to work with since they stick inside the joint.

lowendrachel · #17 10-09-2012, 03:09 PM

Quote:

Originally Posted by Ewo

No need to buy shims. A 3/8" wide strip of business card works fine.

But a shim isn't to fix buzzing, anywhere on the neck. Actually, it's the opposite: to allow you to lower the action more than it already is, when the bridge saddles are as low as they can be adjusted.

From your description, sounds like there's a bit too much relief in the neck, and the D string bridge is bit low.

Thank you Ewo. My saddles are actually high because the strings touched the neck. I've been trtying to tackle this problem since July.

So I have to tigthen the truss rod then? Thanks again.

Rachel

Windreaper · #18 10-09-2012, 03:14 PM

A shim will fix high action around the upper frets. A piece of folded sandpaper on the rear screw holes (punch the screws through the shim) works great in my experience. I recommend 1000 grit for extra growly sound.

bassmeknik · #19 10-09-2012, 03:40 PM

Quote:

Originally Posted by Windreaper

I recommend 1000 grit for extra growly sound.

ah ya...

A piece of sand paper or a slice of business card will work nicely. If the saddles are all the way down and the strings are still to low then the shim needs to be at the edge of the neck pocket not the bottom of the pocket. I use a piece of card stock about 3/8" wide and 2 1/4" long.

mmbongo · #20 10-09-2012, 04:08 PM

Well got the neck off...already shimmed! There's a strip of sandpaper in there. I went ahead and added some business card just to see, now it's fretting out at the upper frets so I'll have to raise the saddles and I think I'll end up with the action right where is was before except now the saddles will be higher.