Misterious reverse shimming on a mustang bass, what should I do?

[Fabio_MIJ]

A Little advice...

Put a reverse shim in. The break angle over the saddles is a bit excessive. You also need to set the witness point on each string at the saddles. You will need to re-intonate, but doing so will add to both intonation and tuning stability.

Nice cleanup job.

You are right Richard, the break angle is a bit at the limit, it may benefit from a little shimming. The guy probably did it for the same reason, but in a very bad way. That metal plate was digging the wood inside the pocket.
Do you think a 0.25° angle may be OK? A full woody ramp Like this:

StewMac Neck Shims for Bass | stewmac.com

I don't have the tools and time to make one myself, I will buy it from the website.

 

[Turnaround]

You are right Richard, the break angle is a bit at the limit, it may benefit from a little shimming. The guy probably did it for the same reason, but in a very bad way. That metal plate was digging the wood inside the pocket.
Do you think a 0.25° angle may be OK? A full woody ramp Like this:

StewMac Neck Shims for Bass | stewmac.com

I don't have the tools and time to make one myself, I will buy it from the website.

You can use a full pocket shim if you like, but I think a partial shim is perfectly fine, despite claims to the contrary. I don't think there will be a loss of tone or that the partial shim will cause a ski jump. I have been trying to induce a ski jump in a neck using a shim. It's been 9 months now and still no sign of even a slight distortion.

If you do go with a StewMac full pocket shim, I suggest you first try a partial shim, say a piece of veneer. I think one thickness of veneer would be enough, but you won't know until you try. When you find what's right you will be able to determine the shim angle that's needed.

 

[Lownote38]

You can use a full pocket shim if you like, but I think a partial shim is perfectly fine, despite claims to the contrary. I don't think there will be a loss of tone or that the partial shim will cause a ski jump. I have been trying to induce a ski jump in a neck using a shim. It's been 9 months now and still no sign of even a slight distortion.

If you do go with a StewMac full pocket shim, I suggest you first try a partial shim, say a piece of veneer. I think one thickness of veneer would be enough, but you won't know until you try. When you find what's right you will be able to determine the shim angle that's needed.

I've also never had a shim cause a ski jump situation, and I've had my share of Fender basses with a ski jump. Not one of them had a shim. Every Fender I've put a shim in has stayed perfectly fine.

 

[Fabio_MIJ]

You can use a full pocket shim if you like, but I think a partial shim is perfectly fine, despite claims to the contrary. I don't think there will be a loss of tone or that the partial shim will cause a ski jump. I have been trying to induce a ski jump in a neck using a shim. It's been 9 months now and still no sign of even a slight distortion.

If you do go with a StewMac full pocket shim, I suggest you first try a partial shim, say a piece of veneer. I think one thickness of veneer would be enough, but you won't know until you try. When you find what's right you will be able to determine the shim angle that's needed.

I've also never had a shim cause a ski jump situation, and I've had my share of Fender basses with a ski jump. Not one of them had a shim. Every Fender I've put a shim in has stayed perfectly fine.

Interesting, in proportion have you found more ski jumps on US, MEX, MIJ, o Squire Fenders?
Lownote, do you usually make partial shims?

Best,
Fabio

 

[Turnaround]

Interesting, in proportion have you found more ski jumps on US, MEX, MIJ, o Squire Fenders?

More often on cheaper instruments mostly because they generally use a poorer quality of wood. But I have seen ski jumps on Fenders and Squiers regardless of country of origin.

 

[Lownote38]

Interesting, in proportion have you found more ski jumps on US, MEX, MIJ, o Squire Fenders?
Lownote, do you usually make partial shims?

Best,
Fabio

Like @Turnaround said, I've also seen ski jumps on every type of Fender instrument including Squier. I agree that it comes down to the piece of wood. Wood does what it wants to.
I use partial shims. I prefer a partial shim made of business card type stock, or a piece of wood with a slight ramp. A little thickness goes a very long way.

 

[Bassdirty]

If it ain't broke....

..fix it 'til it is..

T$

 

[Shooz]

Hi everyone,

I have recently bought a 2nd-hand mustang bass from a local shop.
I have noticed that the neck pocket was shimmed with a thin metal plate so I am making a check during cleaning session. Look at the photos here, it is a partial reverse shim, the job doesn't look top notch.

I guess it does not come like that from the factory, the reason must be to increase the neck angle to solve an action problem, what do you suggest me to do? keep it like that? take it out or replace? At the moment the bass does not have any stability or dead-spot problems,

I will post other photos when the work is finished, the model is pretty nice and unusual: 3T sunburst pawn shop model with one middle-position humbucker replaced by a Dimarzio model one! Tons of low-end power.

View attachment 3589592 View attachment 3589593 View attachment 3589594 View attachment 3589595

Best!
Fabio

I actually just had to shim the front of the pocket on my 2019 jazz bass to get the action lowered properly. Once the shim was added I was able to get the stings much lower with no buzz. I’ve shimmed the rear of the neck pocket before but this was a first, but hey, whatever fixes the problem.
Good luck with your bass!

 

[byacey]

You can use a full pocket shim if you like, but I think a partial shim is perfectly fine, despite claims to the contrary. I don't think there will be a loss of tone or that the partial shim will cause a ski jump. I have been trying to induce a ski jump in a neck using a shim. It's been 9 months now and still no sign of even a slight distortion.

If you do go with a StewMac full pocket shim, I suggest you first try a partial shim, say a piece of veneer. I think one thickness of veneer would be enough, but you won't know until you try. When you find what's right you will be able to determine the shim angle that's needed.

I find that when a slightly thicker shim is needed, A strip of plastic card works very nicely, the cards issued as gift cards, or old Petro-Canada cards, debit cards, etc.