Concaved Bridge Base

[Davii]

I got my '95 LP Standard setup this week, including attending to new saddles I'd fitted, and was informed that my original [nashville] bridge has a slight concave profile developing in it. Probably from string tension over it's 20 year life.

I'd made an attempt to put the notches in the saddles myself, so I'd asked that they were done properly as part of the setup, so now wondering if it's the depth of the saddle notches, rather than the bridge base becoming concaved - is the latter really a likely result after 20 years :?:

 

[Funkfingers]

Re: Concaved Bridge Base

If you want to eliminate the string slots in the saddles of your Tune-O-Matic guitar bridge, go ahead and take measurements.

Next string change, remove the T-O-M. Offer it up to a straight edge. You should detect a very slight bow in the direction of compression under string tension.

 

[Davii]

Re: Concaved Bridge Base

Will do, I should be able to slacken the strings off enough to put a rule against it. He did say it was very slight, and nothing to be concerned about right now, other than the outside strings being higher than they normally would be as a result of needing to raise it slightly.

Just thought it a bit surprising that it could happen to what seems like a pretty solid part

 

[Funkfingers]

Re: Concaved Bridge Base

A good deal of the metal blank has been machined away. This weakens it.

Take it off (without disturbing the height adjustment thumb wheels). Place on a flat surface. In bad cases, the bridge will actually rock from end to end.

 

[Davii]

Re: Concaved Bridge Base

Mine's got a curved bottom to it, so it'll have to be the ruler jobby topside. I think he said it was affecting the wound strings more than the plain side, but I've not had enough time playing it since getting back to see what I think. Bit miffed at another bill heading my way :-S

 

[Boogie Bill]

Re: Concaved Bridge Base

Unusual for a Nashville Tune-o-matic to collapse in the center. They were designed to NOT do this, a common issue with ABR-1 bridges. A collapsed ABR-1 can sometimes be re-contoured.

In any case, for best playability with these bridges, you will almost always need to do some filing of the bridge saddles. This is necessary to match the radius of the strings to the radius of the fingerboard. You can't really eyeball this; you need a set of radius gauges (available from Stew-Mac). Doing this is one of the things that will give you the "...plays like but-tah" feel. This adjustment is equally important to Fender-style guitars and bridges; it's just easier to achieve without filing. For more information on setting the bridge radius, see Dan Erlewine's book, "How To Make Your Electric Guitar Play Great".

Good luck.

Bill

 

[Davii]

Re: Concaved Bridge Base

It appears mine has indeed become concaved. Just had it off, and checked.

Bill - the guy doing it is pretty good, and has the experience/tools for the job, so hopefully the saddles got the right treatment, though I doubt I'm skilled enough to know for certain. Even with gauges :-S

Looks like a new bridge has just gone on the shopping list...yay...

 

[ItsaBass]

Re: Concaved Bridge Base

It happens all the time. I don't think you have done anything wrong.

What you can do, short of replacing the bridge, is to re-radius the saddle notches. I.e., you want to set the bridge height so that the highest saddle slot is in a good place (probably the D or G saddle), then bring down all the other slots progressively in each direction from that highest slot, such that you end up with the proper radius across all 6 saddle slots. If you end up with the strings hitting the bridge behind the saddles, you either just accept that (since there is really no problem with it), or make slots for them.

 

[Davii]

Re: Concaved Bridge Base

A new bridge wouldn't be a disaster, just an unexpected expense. That said, looking at other things guitar that need doing, I may end up saving in other ways, and it being a blessing in disguise

I don't have the tools to rework the saddles, so a new bridge might be cheaper anyway, not to mention feeling a little concerned of making matters worse.