Fret Slot Saws
When you look at the side of your fretboard, you may see the fret tangs inlayed into the fretboard. The fret tangs are seated in what's called the fret slot. The most obvious use for a fret slot saw is to cut the slots in the fretboard for the fret to sit in. Although this is the most traditional use of fret slot saw, it is not the only use. As you may have noticed when you remove the frets of your guitar, there sometimes is debris left in the fret slot. This debris can either be left over glue or chipped pieces of fretboard. Regardless what the debris is, you will need to remove it before you can install the new frets. A fret slot saw is the right luthier tool for this job.
A fret slot saw is simply a small saw that is designed for working in fret slots. It is the right thickness and has the right amount of blades. After the fret wire is removed, you may see glue in the fret slot. Simply take your fret slot saw and run it in the slot to clean out the hardened excess glue. Just be careful. You don't want to saw the slot too deep. The purpose for the saw is to clean the slot, not make it bigger.
There are a few different styles of fret slot saws. Some fret slot saws look like a miniature hand saw with a straight blade. These saws are used for fretboards without binding on the edges. For guitars with fretboard binding, you can't use a standard straight saw like this because you would cut through the binding when you are cleaning out the slot. Instead you need a refret saw. A refret saw consists of two smaller saw blades mounted on a rod. Basically, it looks like a regular fret slot saw with the middle cut out. This design allows you to saw or clean out the fret slots without cutting into the binding of the fretboard. The fret slot saw plays a crucial role in cutting and cleaning fret slots. Without a perfect slot, your frets will not seat correctly and your guitar will most likely suffer from string buzzing.
This is yet another essential tool that every luthier or guitar repairman should have. You will need both a fret slot saw and a refret saw when you are doing fret repairs on people guitars. Both of these saws are handy to own and give more accurate results than trying to clean fret slots with an x-acto knife. If you would like more information about how to use a fret slot saw, please see my how to install guitar frets article.