The bridge of an acoustic guitar is where the string is held for playing. When bridge pins are not seated correctly it can cause problems like being out of tune, string breakage, and physical injury. Ever seen a string slap you in the eye due to improper seating? I have. And it sucks.
Bridge pins pop out when installing new strings
The ball end of the string locks against the bridge plate and prevents the strings from coming out, but once the round hole becomes elongated, it can cause the string’s ball end to pull up into the bridge plate. As the ball end puts tension within the hole, it forces the bridge pin out.
As a means to ease the problem you can put gentle pressure on the end of the string (at the ball end), which will help it to lock into the edge of the hole. You can also turn a fluted bridge pin around, placing the groove away from the string to further close the gap as well. Severe wear will require bridge plate repair.
The ball end of the string wears away at the bridge plate, causing a once round hole to take on a keyhole shape. This wear permits the ball end to pull “up” into the plate instead of locking against it.
The bridge pin itself could also be damaged and not hold the ball end. In stances like this the bridge pins need to be replaced.
Types of Bridge Pins
Fluted bridge pins have a groove cut in them, which provides room for the string to pass between the pin and bridge.
Solid bridge pins require notches in the bridge to accommodate for the strings diameter. Because the bridge pin material can affect the tone and sustain on an instrument, some may desire to try different bridge pin materials.
Some of the materials used include:
- Plastic – Tusq (man made “ivory”), ABS, etc.
- Bone – Ivory (if you can find real ivory) and Bone (from an animal like cow or deer)
- Metal – Alloy, Brass
- Wood – Ebony, Boxwood, Rosewood etc.
Bridge pins come in different sizes. The most common are 3° and 5°. It maybe necessary to fit bridge pins so they will seat correctly. Bridge pin reamers are used to fix this.
A bridge pin reamer normally has only one cutting edge/blade to produce a nicely rounded bridge pinhole. Some manufactures drill holes thru the bridge and bridge plate without reaming it for proper bridge pin fitting. These pins often sit very high on the bridge.
When purchasing custom bone or ivory bridge pins, make sure to inquire about the different bridge pin sizes available. This will allow you to choose the correct set of bridge pins to create a proper fit. If unsure, ream a hole in a test block and check the pins seating first. By following these guidelines, this should prevent some string wear and tuning problems associated with playing and prevent going to an optometrist. Ant Hill Music has a great selection of bridge pins available. Be sure to check them out.