How to stop pickups moving?

[franzbassist]

So I've just installed some Bartolini MK6CBC pickups in a bass.  All great and sounding good apart from the fact that as they are only held in place by one screw at each end they wobble like crazy, plus the screws (#4 pan head 1 1/4" long) are only just long enough for the job.  There are two springs surrounded by foam about 30% of the way in from each end.

 

 

My first thought is to add foam at either end of the pickup, with a small hole cut to allow the screw clear access.  I'd like to steer clear of the central part of the pickup as that's where all the wiring is.

 

 

I also need to find some slightly longer screws, as the 1 1/4" ones really aren't quite long enough.  I thought this would be easy!

 

What does the BC collective think is the best way forward? 

Edited November 19, 2021 by franzbassist

[RhysP]

Big wodge of foam in the pickup cavity. It won't damage the wiring.

[acidbass]

I put foam into most of my pickup cavities.  My advice is to go with thicker foam than you think you'll need (i.e. deeper than the pickup cavity) as the more it's compressed under the pickup, the less movement you will get from the pickup itself.

[franzbassist]

Thanks, both.  Yes, I'm thinking a big chunk under the centre of the pickup between the existing foam/sprong setup should do the job.  I only have pick and pluck at home, which isn't adequate as too soft, so ordered up some closed cell foam blocks to use instead.

[itu]

Do not use a foam that is filled with carbon, if you put it in contact with the bare wires.

[Jus Lukin]

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Edited March 15, 2022 by Jus Lukin

[franzbassist]

A quick update on this. A decent chunk of quality hard foam across the centre of each pickup cavity, plus screws a good 5mm longer than the stock ones, and there's no more rocking.  I did toy with the idea of installing threaded inserts, but I can't see them being needed now the pickups are stable.

 

Thanks again for all the comments. 

[franzbassist]

Ended up adding threaded inserts as well.  A bit belt and braces but the pickups feel rock solid now.

[ped]

I was going to recommend neoprene 'foam' as it compresses much less, glad it's sorted though