What causes a string saddle to have a burr on it?
Most string saddles are made from a metal casting process. This means a casting mold was used to make the saddle. Many of these molds are constructed with two pieces that come together to form the shape of the part. Sometimes there is a small amount of metal that makes its way into the seam created by the two halves of the mold coming together. This seeping metal is called “flash”. The flash is the metal creating a burr on the string seat. It can easily be eliminated by filing away the excess metal.