As I explained in the proper seating of bridge pins article earlier this month, bridge plates can get worn or damaged when strings are not correctly sitting on the bridge. So lets talk about repair and the problems associated with this.
Bridge plates are commonly made from maple or rosewood. They can be made of other woods like spruce, but are not common. It depends on the manufacturer of the instrument. The size and thickness of bridge plates can differ from guitar to guitar. The bridge plate’s purpose is to reinforce the top and keep it from arching or bloating at the bridge where the strings place their tension.
Typical Problems with your Bridge Plate
Wear and tear of bridge pin holes
The ball end of the strings should grab around the edge of the bridge plate and be held there by the bridge pin. When the hole is enlarged by wear (also known as “key holing”), the ball end of the string often pulls itself up into the hole instead of against the plate. This causes the bridge pins to sit improperly in the bridge and bridge plate and could fly out when installing new strings. The ball end of the string wears away at the bridge plate, causing a once round hole to take on a keyhole shape (key holing). This wear permits the ball end to pull “up” into the plate instead of locking against it.
Another common problem is that the thicker string winding which wraps around the ball end can now come too close or even touches the saddle. When this occurs, the saddle may be more prone to damage and intonation can be affected.
Cracked Bridge Plate
It does not happen often, but bridge plates can crack. When this happens it often occurs thru the bridge pinholes. Either the bridge pin has been forced into the hole or the plate over time has just gone bad.
Loose Bridge Plates
When checking for a loose bridge plate I will start by inspecting them with a light and mirror. If there is any doubt, I will use a thin feeler gauge to see there any gaps present.
Bridge plate is warped
I have learned that smaller, thinner bridge plates provide a better tone compared to larger, thicker ones. They may also suffer from warping after years of string tension. The thing is that smaller, thinner bridge plates sound good but often lead to expensive repairs due to warping. As a result, certain manufacturers have gone from too small, to too large, to just about right throughout the years.
A badly warped bridge plate may cause the top to bloat excessively or distort in such a way that the bridge can’t stay glued to the top. This then becomes a bigger, more expensive repair.
Removing Bridge Plates
As many of you have guessed, removing the bridge plate is risky. Heat and/or moisture are often used to soften the glue between the bridge plate and top. Because the top is relatively thin one must not overheat the area, which can damage finish such as the lacquer. Check out this article regarding heat and its affects on instruments.
Getting to the plate through the sound hole leaves little room for tools such as mirrors. For the most part this is done by feel and can get aggravating if you have huge paws. There are a number of hand made tools, which allow users to work under the bridge plate and separate it from the top. Be sure to research the methods and techniques before trying these out and ruining a fine guitar.
Once removed, a new bridge plate is made from scratch and glued in place. To avoid splintering the bridge pin holes, which is commonly seen on inexpensive instruments, the new holes are drilled undersized and reamed using a bridge pin reamer to the correct dimensions. When the holes are drilled improperly, it can cause premature bridge pin hole wear around the hole.
Repairing Worn Bridge Plates
While warped, cracked and loose bridge plates should be replaced, worn bridge pinholes can be repaired without replacing the plate in some cases. There are different ways to repair worn bridge pin holes including plugging and re-drilling them. For simple wear and tear the easiest repair is to install a PlateMate©, which will completely cover the worn holes. This is placed directly over the existing bridge plate and acts as reinforcement for the bridge and prevents further damage.
It can be a pain in the butt trying to string a guitar who’s bridge pins continually pop out when string tension is applied. To ease the effect I recommend you put a little bend in the end of the string at the ball end, which will help it to hook and lock onto the edge of the worn hole. You can also turn a fluted bridge pin around, placing the groove away from the string to further close the gap as well as stated before in our article “Please be seated.” Bridge pins and how they should seat on your acoustic.
As with any repair, research should be done extensively to prevent further damage to your priceless axe. If you are unable to perform a repair, seek an experienced luthier who can do this for you. Replacement bridges are available here at Ant Hill Music.