Repairing a bridge plate

This week I had the pleasure of working on a vintage Gibson LG-1 acoustic guitar, owned by the fantastic musician Seth Walker. These were considered beginner guitars back in the day (the LG stands for “learning guitar”), but now they are starting to command increasingly higher prices as their perceived vintage value rises. It’s not surprising, as they are really great sounding instruments – but this one in particular had a somewhat mushy tone, which I attributed to it’s worn out bridge plate. The bridge plate is a piece of wood (usually spruce or maple) that sits under the bridge on the inside of the guitar, and helps support the bridge and top against the constant pull of the strings. Bridge plates tend to wear out over time, as the metal ball end of the guitar string rests directly against it, and slowly digs into the wood. This results in the string sitting higher and higher in the bridge, so that eventually the loose windings of the string near the end are resting directly on the saddle, like so:

This particular guitar had a very mushy sounding low E string, which isn’t surprising seeing that the string isn’t properly contacting the saddle. Using a mirror and a flashlight, I inspected the damage from the inside – it was looking pretty rough:

This particular bridge plate was worn out enough to warrant a complete replacement, but I opted to repair it rather than replace it completely. Why? Well, this is a vintage instrument, and I believe that they should be kept as close to original as possible (unless I’m specifically asked to modify them, in which case all bets are off). Replacing this bridge plate would not only require an entirely new plate, but would since it’s bolted down through the bridge, I would also have to drill out and replace the pearl dots on the bridge that hide the bolt heads. I felt that replacing the bridge plate would be too invasive, so I decided to repair the existing plate.

To repair the bridge plate from within, without removing it first, requires a specialized set of tools. This one is one of my favorites: my Stewmac Bridge Saver. First, I use the this bit to carve a dome out around the damaged area of the bridge plate from inside:

The bit is reverse threaded, and is turned by hand against it’s threaded counterpart on the top of the bridge, which slowly brings it up into the bridge plate below, carving away a dome shape:

Next I use a special bit designed to make dome plugs corresponding to the shape I just cut into the bridge plate, like so:

These dome plugs are then covered in glue, and pressed and clamped into the bridge plate, and allowed to sit over night:

Here’s a shot of what the bridge plate looks like now, from the inside:

With the plugs firmly in place, I drilled holes through them for the strings to pass through, then sanded the plugs level and cleaned up any excess glue that had squeezed out. Now the ball end of the strings have a solid anchor point, and won’t pull up too high in the bridge anymore. Now the strings correctly contact the saddle:

The mushy tone is gone! With a fairly simple, non-invasive repair, this guitar has gone from just ok sounding to having a robust tone. This thing sounds really, really good – it’s too bad I have to give it back!

Permanent link to this article: