Options for a FB that is too flat.

[JtheJazzMan]

So I need to increase the FB curvature on one of my basses for an even arco-friendly curve. The only option I can see is to shave off wood on the E and G sides, but is there a general rule as to the minimum thickness on the edges?

Does that Chuck Traeger book have any info pertaining to this?

[keiranohara]

Before you go carving down the FB, what about adjusting the profile of your bridge. The bridge profile effects the bowablity much more directly. Generally, I look for string heights of 5, 6, 7, and 8mm under the G, D, A, and E respectively. But often one will have to fudge a bit on the A and D making them higher off the FB to allow for bow clearance. This would be doublely so if the FB has what is called a romberg shelf (a flat facet under the E string), making one of those bowable may take as much as an extra 3mm under the A.

[bigolbassguy]

Originally Posted by keiranohara

Before you go carving down the FB, what about adjusting the profile of your bridge. The bridge profile effects the bowablity much more directly. Generally, I look for string heights of 5, 6, 7, and 8mm under the G, D, A, and E respectively. But often one will have to fudge a bit on the A and D making them higher off the FB to allow for bow clearance. This would be doublely so if the FB has what is called a romberg shelf (a flat facet under the E string), making one of those bowable may take as much as an extra 3mm under the A.

+1

If you have an adjustable bridge, this would be an easy fix.

[Hector Wolff]

When I read the original post I assumed that the bridge was not the problem.

Assuming that the bridge is also too flat for good arco, then recutting the bridge to have a greater curve without also similarly curving the fingerboard will just make the bass more likely to buzz along the E and G strings or harder stop cleanly along the A and D strings especially as you move up the board.

The two have to be cut to work together.

Raising the height of an adjustable bridge will not make it easier to bow if it was too flatly cut. If the bridge was properly curved for arco and only the fingerboard was too flat, then raising the bridge would stop the buzzing, but not fix the resulting excessive string height in the center.

[Matthew Tucker]

Originally Posted by JtheJazzMan

So I need to increase the FB curvature on one of my basses for an even arco-friendly curve. The only option I can see is to shave off wood on the E and G sides, but is there a general rule as to the minimum thickness on the edges?

Hector is absolutely right, the FB curvature and the bridge crown have to work together.

You can remove as much wood at the edges of the FB as you like; the thing you DON'T want is a flexible fingerboard. The more you take off, the more flexible it gets, but its hard to say when to stop without being there. So it can be done, but you also have to watch what happens to the longitudinal scoop!

It amounts to a full fingerboard replane job really. If you have plenty of thickness to start with you'll be fine but if you're planing an older fingerboard that has been redressed a few times, it might be better to get a whole new FB fitted. Without seeing the bass, I think if you have at least 10mm at the edges of the FB you may have room to move, but if you have much less than that already, it's getting a bit iffy.

[bigolbassguy]

Originally Posted by JtheJazzMan

So I need to increase the FB curvature on one of my basses for an even arco-friendly curve. The only option I can see is to shave off wood on the E and G sides, but is there a general rule as to the minimum thickness on the edges?

Does that Chuck Traeger book have any info pertaining to this?

Yes, it does. Chuck Traeger would always leave the A and D strings a couple of mm high when he set up a bass, then adjust the setup to suit the player's tastes. I don't think it's very practical or cost-effective to redress the fingerboard every time you deepen a string slot.

If you have an adjustable bridge, you can probably raise it a couple of mm and lower the action on the G and E without hurting anything. It isn't ideal, but - for example - it is the only way to make an old Kay bowable without replacing the FB.

[Matthew Tucker]

MOST basses I see have a bridge crown cut much steeper than the fingerboard curve to give a better bow clearance. But yes, this causes A and D to be higher and gets harder to finger once you get past the neck joint. So to have the arco clearance AND have the nicest string height, you need to work the fingerboard as well. Lovely when it all works together.

However, its a fair bit of work, costs the player, and if most of your "money" notes are played on the neck, you're right, it's probably not worth the bother.

[bigolbassguy]

Originally Posted by Matthew Tucker

MOST basses I see have a bridge crown cut much steeper than the fingerboard curve to give a better bow clearance. But yes, this causes A and D to be higher and gets harder to finger once you get past the neck joint. So to have the arco clearance AND have the nicest string height, you need to work the fingerboard as well. Lovely when it all works together.

However, its a fair bit of work, costs the player, and if most of your "money" notes are played on the neck, you're right, it's probably not worth the bother.

Unfortunately, it can make the G string sound a little nasal in relation to the other strings + stopping the A and D aren't the only issue, it may remain difficult to bow in thumb position because of the increased deflection of the strings.

Maybe you could post some pics.

[Matthew Tucker]

Fingerboard and Bridge relationships