My knob keeps falling off.

[project_c]

Sorry, couldn't resist that title, but this is a legit question - I have 2 precisions, and the knobs on both basses keep coming loose and falling off whenever I take them out in a gig bag. Both basses had new grub screws put in, because I thought that the problem was they were old and worn out, but it's still happening. Is this a normal thing? Is there a solution to this that everyone knows about except me?

There's nothing major happening in transit, I have cables in the pocket of the bag, perhaps a pedal, nothing else, the basses travel with me in the front seat of the car, or on my back on London transport. Maybe it's nothing to do with them being in transit, not sure.

[Guest MoJo]

Are the pot shafts split or solid?

[ahpook]

Has to be done folks...

[media]http://www.youtube.com/watch?v=byDiILrNbM4[/media]

Edited May 12, 2016 by ahpook

[project_c]

[quote name='ahpook' timestamp='1463056472' post='3048145']
Has to be done folks...

[media]http://www.youtube.com/watch?v=byDiILrNbM4[/media]
[/quote]

it's only fair.

[quote name='MoJo' timestamp='1463054715' post='3048116']
Are the pot shafts split or solid?
[/quote]

I just looked and it's split on one bass, solid on the other!

[Hobbayne]

A dab of nail varnish on the grub screw should keep it from untightening.

[Guest MoJo]

[quote name='project_c' timestamp='1463061905' post='3048212']
I just looked and it's split on one bass, solid on the other!
[/quote]

If it is a case of the grub screws coming loose, yes a dab of clear nail varnish should prevent that. When using control knobs with grub screws on split shafts, I always make sure that the screw lines up with the gap in the shaft, thus acting as a wedge when you screw it in.

[project_c]

thanks. where do you actually put the varnish? inside? or at the head of the screw?

[Grangur]

[quote name='project_c' timestamp='1463123440' post='3048726']
thanks. where do you actually put the varnish? inside? or at the head of the screw?
[/quote]
Take out the screw, put a dab on the thread and put it back in and tighten. That's how I've used "Loctite Threadlock" anyway.

[pfretrock]

[quote name='project_c' timestamp='1463061905' post='3048212']
it's only fair.



I just looked and it's split on one bass, solid on the other!
[/quote]

Terrible things split shafts, have no place on a Precision.
Make sure the grub screw bear on the split and not the other part of the shaft. They are really meant for push on splined knobs.
Careful with the Loctite, use the wrong grade and it won't ever move. this might not be what you eventually need.

[project_c]

Thanks for the relies, I'll try the nail varnish, sounds good. with the screw on the split shaft, I don't think I can do that because I like the screws to be in a specific place (pointing at me) to show me when the volume is on full (it's a precision habit I inherited when the guy I bought my first p from had his set up like that), but the nail varnish should do the trick hopefully.

[Bassassin]

You can make split shafts compatible with set screw knobs by packing out the split - I've used slivers of thin plastic card pushed tightly into the gap and it's perfectly stable.

Superglue makes a good improvised threadlock for set-screws - use a tiny spot on the thread, and it will prevent it from vibrating loose, but is brittle enough to be easy to undo when necessary.

Jon.