Pickup cavity too small - which dremel bit do you recommend?

This should do it.

 

This should be done with a router.

 

Dremel makes a 1/8” router bit. One was included with all of the accessories when I purchased mine years ago.

 

I’m glad I read this. I too have an Indo P/J, and have considered upgrading pickups (hardware, etc). I always thought the pots were the only potential obstacle to doing so.

 

It will be hard though not impossible to do a clean job of this with a hand held tool like a Dremel. A router with a template is the right way to go. If you are tempted to try with a Dremel, I would suggest you practice on scrap wood of the same type as your bass body. Only touch the bass when you get consistent results. Also if your bass has a poly finish it may crack when you work on it. Try scoring it with a razor knife.

 

You can use a Dremel for slightly enlarging a pickup cavity, but you need to do it gently and carefully. You are cutting freehand, so you need to work slowly and keep it smooth and straight.

Don't use the sanding drum, it clogs up too easily on hardwoods. I also don't recommend the router bit, unless you are using the Dremel in the router base. The router bit only has two cutting edges, so it digs and grabs more when cutting freehand.

Use a standard Rotary File Burr, with multiple spiral cutting edges, like these:
https://www.amazon.com/Carving-Hand...8&qid=1524579861&sr=8-29&keywords=dremel+bits
Use the cylindrical ones, like the two on the right. That will give you the smoothest cut, with a gentle feel.

 

Cylindrical style tips leave a smooth finish if you have the skill to hold it precisely with your hand. a teardrop style carbide tip is the easiest to use will give you the most control.

 

I have had success using the dremel cutting guide and clamping a carpenter’s square in position for the cutting guide to ride against (like a router template) to get good, clean cuts.

 

Maybe: Return the pickup and get a neck position jazz pickup. For a while there, Squier was using neck width pups in both locations, hence the smaller rout.

 

I just finished dealing with this exact situation on a PJ bass pickups upgrade. What has worked well every time is:
(As RSBBass also commented) use a NEW razor blade to gently cut through the finish to prevent rip-outs. Use a straight metal edge as a guide and make multiple light passes to get depth. I recommend trying to go down at least 3/32". This gives you a bit more room for error when using your Dremel.

Keep in mind you can always take away a little more but you can't put it back - go slow and easy. Take the precautions to protect the finish and make an even cut at the top. Anything in the cavity will disappear when you cover it with black conductive shielding paint.

INSTALLATION TIP: Use the existing pickup screws as they will fit the existing threads in the body. This can save you from having to do a lot of unnecessary extra work.

 

If you don't mind you can just sand or file off some plastic from the end pieces of the pickup.

Won't effect their functionality.

Not if the screw "ears" of the pickup fits with the current pickup, traditional jazz bridge and jazz neck have them placed slightly different.

 

Keep in mind that the ears bear the main burden from screw tension. If the plastic is made too thin it will become susceptible to fracturing from pressure when you tighten screws.

 

The ears are on the sides not the ends of a Jazz pickup.

 

I think you’re missing the point. Location is irrelevant. Cutting on covers is a bad idea.