Increase the size of the control cavity on a Precision

[Delberthot]

I recently bought a new scratchplate for my Precision so that it has 3 holes instead of the 4 the original one came with. It's a perfect fit except the blend pot which is where the output jack normally lives won't fit inside the control cavity.

What's the best way to enlarge the cavity to make it fit? I don't want to go to the expense of buying a router for such a small job as I'd never use it again. I had thought about a rasp and file set but don't want to trash the bass

[BassBus]

Take it to Chris Mcintyre in Edinburgh. Renowned luthier with a high degree of perfection to his work. Might even be able to do the job while you wait.

http://www.mcintyreguitars.com

[KiOgon]

Fit a smaller blend pot CTS do a good 250K mini with centre detent.

[KingBollock]

I have used a small sanding barrel in either my Dremel or attached to a cordless grill, for doing that job.

Something like this:



Dirt cheap from Wilkos and general DIY stores.

Edited February 5, 2015 by KingBollock

[pfretrock]

[quote name='KiOgon' timestamp='1423127342' post='2680986']
Fit a smaller blend pot CTS do a good 250K mini with centre detent.
[/quote]

Do this in preference to machining.

Not sure how common this is but on my MIM P there is only a few millimeters of body under the scratch plate near the output jack position. You may expose the cavity!

[hamfist]

[quote name='KingBollock' timestamp='1423127600' post='2680991']
I have used a small sanding barrel in either my Dremel or attached to a cordless grill, for doing that job.

Something like this:



Dirt cheap from Wilkos and general DIY stores.
[/quote]

Yes ! but I echo pfretrock's warning about exposing the cavity.

If you are confident you are well away from exposing the cavity a file and some sandpaper will do the job, but you will reduced resale value on an expensive bass that way.

[chris_b]

If you're going to increase the size of the cavity, work towards the front of the bass, towards the neck, then you can reinstate the original scratch plate without any of this work being visible.

I'd get some stacked pots.

[Ghost_Bass]

An idea. Before you start carving attach the pickguard and use a permanent ink pen (the kind that washes away with alcohol) to trace the outline of the pickguard so you know that you won't be exposing the cavity when carving. This only works with laquer bodies, don't do it on a unlaquered body

[pfretrock]

[quote name='Ghost_Bass' timestamp='1423136784' post='2681160']
An idea. Before you start carving attach the pickguard and use a permanent ink pen (the kind that washes away with alcohol) to trace the outline of the pickguard so you know that you won't be exposing the cavity when carving. This only works with laquer bodies, don't do it on a unlaquered body
[/quote]

I did this, but put masking tape on first! (and used a pencil). I found the route only just big enough for a Switchcraft style jack, and very close to the pickguard edge. So I chopped a bit off the replacement jack (different type to Switchcraft) to get it to fit. The route was only deepened a bit further along to fit a switch pot.

[Delberthot]

Thanks for the tips. The problem is that I have EMGs fitted to the bass and the pots that come with it with the push fit cables are quite a bit bigger than standard