Help with my String/Bridge Height

[Calvin Marks]

Originally Posted by Arnold Schnitzer

Calvin, it's important that the fingerboard arch be set properly before the bridge curvature can be worked out. If the fingerboard is too flat (cross-ways) the outside strings will have to be low or you won't be able to bow the bass. If you are going to use 25mm spacing at the bridge, which is quite narrow (27-28 is "normal"), the fingerboard will need to be more arched than usual. I hope this is clear and helpful...

Thank you for the reply. Very clear, very helpful. The bass came with 25mm, and it bows fine, so I'll leave it that way. Seems that I need the fingerboard plained properly and then the bridge set-up in accordance with 4,5,6,7or8.

[Calvin Marks]

Should the strings fit IN the bridge/nut grooves or over? My G-string if fairly thin in gauge (Pirastro Flat-Chromesteel) so it has a lot of space in the bridge slot, whereas the rest of the strings are on top of the groove.

[Arnold Schnitzer]

I like the strings to sit about 3/4 of the way down into the groove. And I want the groove a few thousandths wider than the string. (Don't you just hate words like "thousandths" with five consonants in a row? Doesn't exactly roll off the tongue, does it?)

[Calvin Marks]

Are there any tools you can use to do this yourself? (the bridge filing, grooving).. Would I just need a rat-file and some graphite and a micro-ruler?

[Joel Larsson]

A thin needle-type file is one handy tool. If you get yourself a FB planing and a new bridge, I'd recommend getting a slightly high-ish cut, as some luthiers do seem to think that as long as it doesn't rattle, the string should be as low as possible. With one of these, it's a piece of cake to file off some excess wood. (But some carefulness is advised, as wood can be filed away but not put back!) If you think you have filed them too far into the bridge, any luthier will be able to file down the bridge until your strings rest as deep down in the grooves as you want 'em. You could even do this yourself if you're not afraid of a displaced sound post of misplaced bridge - I sure as hell wouldn't, but that's just me. You'll also become every other student's best friend, as you're hardly the only one with setup issues!

Anyways, if you think you couldn't handle higher strings for solo playing in thumb position, you MAY have a slightly too concave fingerboard. I played this one bass that had been set up by a violin specialized luthier. You couldn't play it as the vertical shape of the FB made each string rise very steeply. And yet you couldn't file down the bridge, because then the strings would rattle against the end of the FB. Consequently, the string height at the en of the FB was very (too) low but at the highest spot, I'm not joking when I say it was at least 15mm even on the G. If you have noticed even the slightest tendency towards this, a planing is indeed to be considered. It sounds strange that there should be no good bass guy in the area. Where does Joel Q repair his instruments, for instance? Send him a mail, for all I know. I think you can do that if you click on his profile.

Oh, and! Congrats on the successful audition! It was your first, right?

[Calvin Marks]

Thanks to Joel and Arnold for the great advice. Much appreciated, guys!

[Pino Cazzaniga]

Calvin,
your fingerboard is too flat for the string spacing / bridge curvature you like, as Arnold said.

If you will make it planed with the same curvature of your present bridge, you will not lower as now the A and the d strings when you press them to the fingerboard in high positions.

The more the fingerboard is concave, the more this effect is noticeable

So, probably you will need less bridge curvature for the same bowing.

A way is to plane the fingerboard with a bit less arch than the one of your present bridge, and then to set up the bridge again.

Find a good luthier to do this.
A good luthier is someone who can listen you, realize what you really need, share with you his opinions and make the work.

Is the fingerboard thick enough to plane it?
Have you adjusters on your bridge?
Are you going to play soon for auditions?