Advice on screwing Bigsby B5 onto uneven Telecaster top

Evan

I’ve just stuck a B5 on my Tele - partscaster, the top of which is far from flat and there’s no way of tightening the mounting screws I can find that doesn’t end up with the arm tightening up a bit, and not flopping around freely like it does on the Dylan talks tone video I watched on YouTube. 

Does it matter? I’ve got no idea whether it’s affecting the performance of the Bigsby. I played for an hour yesterday, applying lubrication and looking for causes of tuning problems, which I suspect will be going on for a while yet. When I first strung up (bloody nightmare) and started playing it went instantly out of tune every time I touched the tremolo, but after I’d been playing for a while it settled down and seemed to be behaving quite well. 

Any tips, advice (keep smart arsed Bigsbyphobic comments to a minimum please) much appreciated. 

https://youtu.be/ww5WjsXYI4Y

ICBM

Yes, it matters - unless the arm can move completely freely when there's no string tension on it, it will cause tuning trouble.

If you can tighten the two rear screws down and leave the others loose enough that it doesn't twist the frame, that should work. It may be best to fit felt pads or rubber grommets under it - you may need larger screws as well.

Evan

ICBM said:

Yes, it matters - unless the arm can move completely freely when there's no string tension on it, it will cause tuning trouble.

If you can tighten the two rear screws down and leave the others loose enough that it doesn't twist the frame, that should work. It may be best to fit felt pads or rubber grommets under it - you may need larger screws as well.

Morning ICBM, quick on the trigger again. It’s not that it’s really tight, it just doesn’t fall down on its own the way it does in the video. It doesn’t seize up or anything, it just needs a bit of encouragement. 

I did leave the felt pads on - do you mean I should add more? Longer screws or just fatter?

ICBM

If you’re going to put grommets under it, longer.

Basically it doesn’t matter if it’s really tight down as long as it can’t move - the string tension will hold it in place… bear in mind that the B3/B6 aren’t attached to the top at all, and the hinge is quite loose. But even the smallest amount of excess friction in the bar bearings will cause trouble.

PAL

If you tighten a Bigsby to a guitar top and it's uneven it can distort the Bigsby and it stiffens up ! it can help using felt washers.
  Try and keep the bottom of the unit flat this will ensure the trem doesn't lockup anywhere. Hope this helps.
  
  

Evan

Right, I’ve tightened all the screws just enough to stop the Bigsby from moving and just short of the point where the arm movement is impeded and it’s helped a lot. I’ve been playing it for a couple hours and the tuning stability is much better. 

Thanks for all the help - I expected tuning issues but I didn’t anticipate this problem.