Double Bass Lowering the bridge

[Rees Chapman]

The adjustable bridge on my Christopher bass (w/ solid top) is so tall, even at its lowest setting, my string action is painfully high. My teacher suggests I take it to be shortened, perhaps as much as 1/4 inch, but I can't make it to a luthier in the big city for several weeks. So, I'd like to try it myself.

I want the bridge to be low enough that the adjusting wheels have a little bit of range, so I'd take it a little lower than I need, and adjust upwards.

I'm aware of two approaches:

1) carve down the feet. I've read where I can carefully saw off a little less than I need, then strap some sandpaper over the top where the bridge stands and drag the feet back & forth across it (matching the angle to fit the top).

2) leaving the bridge in place, deepen the string grooves (one at a time, checking the action), then sand down the edge to fit the groove depths.

1) leaves the feet thinner, and risks a fallen soundpost, while 2) fattens the edge where the strings cross.

Suggestions (including DON"T DO IT!) would be appreciated.

Rees

 

[Bob Gollihur]

PM sent, I'll be glad to email you the bridge instructions I've written.

 

[Jake deVilliers]

A picture would really help but.........2) is probablythe better approach.

Make sure that there will be at least an inch and a half of wood left above the heart.
And you'll need to re-contour the bridge so that the original thickness at the top and the smooth wedge-shape is retained.

Good luck.

 

[Brent Nussey]

Suggestions (including DON"T DO IT!) would be appreciated.

Rees

#1) Don't do it! The sandpaper method does not work. A proper luthier will carve the feet to match the top. If your feet have been properly fit, you'll never get it as good as it is now, especially with the bogus sanding method. And as you mentioned, the feet will not have correct thickness where they meet the top. To take off enough without really damaging the feet seems to be unlikely.

#2) Don't do it-maybe. Seems like you could have better luck with this method, but the bridge has a number of thicknessing issues and various compound curves you should know about before reshaping your bridge, which is what you'll really be doing.

My best suggestion would be to remove the wood from the legs of the bridge (or maybe feet of the bridge) *where they meet the adjuster* you can borrow/rent a disk sander, mark how much you want to take off, and sand it off square and true. Sand the surface square to the bottom of the bridge (assuming your bridge is carved properly to begin with..). The easiest way is to remove wood from the side where the hole for the unthreaded portion of the adjuster goes in. Just make sure there's enough room for the adjuster to still fit correctly after removing the wood. Also make sure that you remove the exact same amount from each leg, to keep everything true and square.

I think that the average person can do much better with this method than trying to reshape the compound curves of a bridge, and I've seen at least one very experienced luthier use this method too.

Good luck,
Brent

Edit-I can draw a picture if what I'm saying isn't clear. Don't sand the feet of your bridge... please.

 

[bpclark]

If you are going to mess with the bridge, then I would say that Brent's suggestion sounds to me like the most sensible approach. Based on a conversation I had with luthier once about fitting the feet on a bridge that has already been cut for adjusters, I would advise against going with option #1.

And since it sounds to me like this bass has not had a proper setup (hence your problem), be sure to check the string clearance at the nut. It shouldn't be much more than the thickness of a business card. I mention this because my son played a school-owned Christopher(that was not setup correctly) and it was painful to play because of the spacing at the nut. I pretty much told him not to use it and took it to a luthier because I was worried about the risk of injury. Once the nut was done it went from being the most unpopular school bass to one of the most popular ones.

 

[Nils Ö]

Don't do it

At least not if the bridge is of otherwise good quality.

Depending upon what kind of adjusters you have, perhaps you could remove them temporariiy and use something else in their place? (Two brass pins and some washers to get a reasonably correct height). Just an idea, I haven't tried it.

 

[Picknbow]

Your bass is probably at a point in it's life (a year or two old) where it needs it's first real set-up by the best person you can find.

If you absolutely have to do something, limit it to lowering the string slots while the adjusters are both open exactly one turn. At least obtain the proper file. Usually the grooves at the nut need deepening as well. With this approach, the bridge can still be properly fit a a later time.

 

[Keyser Soze]

Your bass is probably at a point in it's life (a year or two old) where it needs it's first real set-up by the best person you can find.

In my opinion, this is the best advice yet offered.

I bought a Christopher bass that was drop-shipped to me directly from the Christopher distributors. It arrived with exactly the same bridge symptoms that you describe.

Part of my "plan" in buying the bass was to have "the best" local luthier do the set-up, rather than the "luthiers" who worked for the two local Christopher dealers. In that I got a great deal on the bass, paying a premium fee for top notch luthiery afforded me a far better set up bass for far, far less than I would have paid had I bought it through either of the local snakes.

Not only did the bridge need to have material removed from above the adjusters but it needed to be proplery shaped. The soundpost arrived cut at 90° angles; that obviously needed to be cut and fitted properly. The fingerboard had never been properly planedand dressed and the nut needed to be filed. The tailpiece needed to be adjusted. The endpin reaming was cock-eyed.

Unless you've had ALL of the stuff done that your bass requires, you're really shortchanging yourself as far as playing a bass that is really in substandard condition, not "all that it can be."

You'll have to drop a fair amount of dough to get all these things done well but, I guarantee you, once you get your bass back after these things have been done, "night and day" will not begin to describe the before/after sound and playability of your bass.

The initial cost of all of this might seem high but just amortize it (in your mind) over every minute you play the bass from now 'til...

You'll kick yourself in the butt for not having it done sooner. I've had my bass for 4-1/2 years now and I couldn't be happier.

 

[Brent Nussey]

In my rush to keep you from messing up the shape of your bridge's setup, I hadn't really considered that it might not have been properly set up at all yet. That would explain the action you're describing. You really should take it to a luthier for proper setup then. My advice was only intended for an already cut and shaped bridge that just needed to go down a bit more. If it's like I'm now imagining, the bass needs a proper set up all round, and if you go mucking around with it, you might likely make it worse or harder to fix, and that may not be a good way to start a positive relationship with your luthier. That can be an important relationship to get off on the right foot.

Brent