Thursday, February 4, 2010

Don't Fret, Part 2: Slotting

Yesterday I covered how to prep the fretboard for slotting.  If you follow my recommendations, you should have a fingerboard blank which has been cut to the minimum dimensions, and has been marked for slotting.  Today, I will cover all the final preparations to the fingerboard. 

Cutting the Slots

Only simple tools will do...

Choosing the right saw is a very important part of doing a fret job well.  Fret wire has a narrow root called a tang that is inserted into the fret slot.  However, the width of the slot should be slightly larger than the width of the tang.  Fret wire has tiny, diamond-shaped barbs on the tang, which compress the fibers along the slot wall, holding the fret in place. 

Fret wire does it with tang...

Most fret wire on the market today requires a 0.023" slot width.  My hobbiest's razor saw has 0.015" kerf, though in practice, it cuts around a 0.020" slot, which is sufficient, and holds frets very well.  

Note: Reducing slot width has the additional effect of producing back-pressure on the neck, which helps the neck resist the bowing effect of string tension.

Before you begin cutting your precious fingerboard blank, use a scrap to test your saw.  Measure the kerf using feeler gages.  Using a caliper, measure the width of the tang, (not including the diamonds).  If the slot width is smaller than the tang, it is too small!

Electrician's tape makes a great depth gage.  Mount tape on the side of the saw that corresponds to your dominant hand.  Other types of tape work as well, but will stick to your saw and are annoyingly hard to remove.

Go ahead and pound a fret in.  If this is the first time you've done it, spend some time fretting scraps around the shop until you feel comfortable.  The goal, for now, is just to verify that your slot size is adequate. 

Also, please be aware that there are purpose-made fret saws out there.  Just visit my friends at  Remember, you always pay more for specialty tools.  Razor saws are less than $10.

Moving on...

Position the try square on the fingerboard blank so that the try square blade is aligned with the first fret mark.  Holding the square with firm pressure, hold the saw with your dominant hand and begin cutting.  After a few strokes, the saw will become it's own guide. Turn the try square up to use as a perpendicular guide.  Cut down just to the bottom of the tape.  Twenty-two fret slots can be cut in about 40 minutes using this method.

Cutting the frets is quick and easy, just make sure your cutting in the right spot...

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