Shim a 5 bolt neck same as a 4 bolt neck?

ThingsAbove · #1 11-17-2011, 12:38 PM

I have a 5 string Peavey Millennium ACBX that I recently purchased used.

The action is high when the neck relief is properly set and there is very little height adjustment with it's bridge design. I'm as low as I can go there and it's still uncomfortably high especially at the G and B strings.

I've shimmed a few necks before but they have always been 4 bolt.

Since the 5 bolt neck has an uneven number of screws on each side, when I place a shim at the back of the pocket is there a problem due to 3 screws on one side and two on the other causing it to pull unevenly? I've put a single thickness portion of a business card in there and it's not enough. I'm just concerned that if I give it 0.5mm thickness shim it might create uneven pressure with the odd number of screws and cause the neck to twist or the body to neck joint to crack.

Should I be concerned?

tangentmusic · #2 11-17-2011, 12:45 PM

A shim is a shim. Get the neck height up to where you can start adjusting the bridge to your desired action. Leave enough bridge adjustment for intonating.

ThingsAbove · #3 11-17-2011, 02:04 PM

Alrighty then... shim shim sharoo

walterw · #4 11-17-2011, 09:37 PM

to assuage your fears, use another, thinner shim between the primary shim that's setting the desired angle and the other end of the neck pocket. lay a straightedge across to find the spot where this "step" shim is on the same incline as the primary shim and the edge of the neck pocket, so it shares in supporting the pressure along the neck pocket. glue it in place, of course.

(nothing to do with the number of neck screws, by the way.)

ThingsAbove · #5 11-18-2011, 10:09 AM

I used two biz card thickness, graduated with one being double the length of the first shim.

One biz card thickness wasn't enough and two is just about right it seems to be even across the neck so I guess the asymmetrical bolt arrangement didn't cause a problem.. yet. The neck pocket creaked for a while after stringing it up so I may need to use a piece of sandpaper in there for the shim rather than slick biz cards. One bass I took apart had sandpaper for a shim. I don't know if it was intentional or just what they had handy.

According to the specs this Peavey 5 string has a 14" radius neck which seems to have more curve than other 5's I've owned. They even radiused the pickup covers so that's a nice touch for an inexpensive bass.

MNAirHead · #6 11-21-2011, 09:08 AM

I use layers of slim masking tape. Easy to dial in doesnt move

grendle · #7 11-22-2011, 08:46 PM

Quote:

Originally Posted by ThingsAbove

I used two biz card thickness, graduated with one being double the length of the first shim.

One biz card thickness wasn't enough and two is just about right it seems to be even across the neck so I guess the asymmetrical bolt arrangement didn't cause a problem.. yet. The neck pocket creaked for a while after stringing it up so I may need to use a piece of sandpaper in there for the shim rather than slick biz cards. One bass I took apart had sandpaper for a shim. I don't know if it was intentional or just what they had handy.

According to the specs this Peavey 5 string has a 14" radius neck which seems to have more curve than other 5's I've owned. They even radiused the pickup covers so that's a nice touch for an inexpensive bass.

Sand paper is about the best you can use. The grit count insures its an even thickness. If its creaking, the neck is not set properly in the pocket. Loosen the neck screws up a few turns with the strings on (loose) and then tighten them up about to pitch. They will pull the neck in to where it should be. Tighten the screws.

grendle · #8 11-22-2011, 08:49 PM

Quote:

Originally Posted by MNAirHead

I use layers of slim masking tape. Easy to dial in doesnt move

Bad idea, it has about the worst consistency in thickness and will flatten out uneven as well.

walterw · #9 11-22-2011, 09:35 PM

i haven't tried it myself, but dan erlewine likes the masking tape, pointing out that (as a paper product) it's still "wood".

the idea is that you can easily layer the tape to create a consistent ramp for fully supporting a neck in the pocket. like "4 layers at one end, then 3, then 2, then 1, then none, then the other end of the pocket."

ThingsAbove · #10 11-23-2011, 08:58 AM

Quote:

Originally Posted by grendle

Sand paper is about the best you can use. The grit count insures its an even thickness. If its creaking, the neck is not set properly in the pocket. Loosen the neck screws up a few turns with the strings on (loose) and then tighten them up about to pitch. They will pull the neck in to where it should be. Tighten the screws.

The neck creak stopped after it was tuned up and I yanked on the neck a little to settle it in. It's all sweetness and buttercups now. The action is as near perfect as I'll get on this inexpensive bass.

grendle · #11 11-24-2011, 10:29 AM

Quote:

Originally Posted by ThingsAbove

The neck creak stopped after it was tuned up and I yanked on the neck a little to settle it in. It's all sweetness and buttercups now. The action is as near perfect as I'll get on this inexpensive bass.

Cool!

grendle · #12 11-24-2011, 10:31 AM

Peavey dosent have a neck adjustment screw on those? I think those need to be manditory on all bolt ons. Makes life easy.

Pilgrim · #13 11-24-2011, 11:09 AM

You need a 5-screw shim; they are very rare and must be hand-crafted. I will create one for a small fee.....

ThingsAbove · #14 11-25-2011, 06:12 AM

Quote:

Originally Posted by Pilgrim

You need a 5-screw shim; they are very rare and must be hand-crafted. I will create one for a small fee.....

5-bolts wasn't the issue. It was the asymmetrical nature of the bolt pattern and the thought that it would apply uneven force to the neck when the shim raised one end.

mongo2 · #15 11-25-2011, 06:55 AM

Quote:

Originally Posted by grendle

Bad idea, it has about the worst consistency in thickness and will flatten out uneven as well.

I've used it for decades on many instruments in lieu of a wedge of wood for full contact shims and it works fine.

The ability to use thin strips of tape to build up thickness allows the use of various styles of layering to correct neckpocket/neck fit anomalies.