screwing or bolting down a bridge?

[slowesthand]

This may seem like an odd question ,but.... I have a friend whose 12 string bridge has lifted for the second time. This time he says he is just going to drill holes, one on each end of the bridge, and bolt it down adding a small backing piece of wood on the inside to bolt through.

My question is, would that affect the tone of the guitar? And if so I wonder how much it would affect it.

Thx ahead time for any replies.

[Rodger Knox]

That might work, there's quite a few old guitars that have bolts or screws holding the bridge down. Don't drill the holes through the X brace, that would be bad. It's hard to say what effect it would have on the tone, a little more weight on the bridge could have a significant effect.

The correct repair is to remove, clean, and reglue the bridge. If it's prepped and fitted properly, HHG or Titebond should hold just fine.

[Alan Carruth]

Any time you put hardware into wood it's a stress riser. Any distortion gets concentrated in that area. I'm pretty sure that it won't make the joint usefully stronger; it just makes more damage and a tougher repair later on. I did a lot of those repairs back in the day, and never enjoyed them.

The exception to that would be if you used a fairly large and rigid bridge plate inside. Then the extra mass and stiffness would go a long way to kill the sound.

The real fix for a bridge that won't stay down in a bigger bridge. Even then it won't work if it's not glued to a top that is in decent shape. Do you know what sort of top his guitar has? If it's laminate, and the bridge has come up twice, I'd expect that the top ply is gone, which weakens the top a lot. Even if it's solid, if there has been and loss of wood on the surface that's a problem. If the bridge was simply re-glued to a rough surface you've lost a lot of the strength of the joint. If the wood was taken down a bit to make it level to glue to the top has also been weakened.

Enlarging the footprint of the bridge reduces the stress in the glue line. It's particularly effective if the bridge is made deeper along the line of the string pull. That's what Martin did when they replaced the 'bar' bridge with the 'belly'. Even a little bit wider can reduce the stress along the back edge quite a lot, and since that's where the lifting starts that's place to make improvements. By substituting a less dense wood for the usual rosewood or ebony you can keep the mass of the bridge down while still making the footprint larger.

[Truckjohn]

There are pix all over the web of bridge bolts that pull right through the bridge plate and top - leaving a gigantic mess.

One thing I would suggest trying is to lay some sandpaper on the top and sand bottom of the bridge to match the top profile. Many (most) guitars glue a flat bridge to a curved top.... This can lead to the bridge wanting to pull loose along the back and out on the wings.

I would match the bottom of the bridge to the curve of the top whether or not a larger bridge profile is used.

[Parlorman]

Bad idea. If the guitar is worth keeping, he should have the bridge properly repaired.