Fretting, as in working to install the frets into the fretboard. The tolerances are so close it can become something to fret about.
The slot must be the right width to hold the fret wire tang securely, but not so tight that driving the frets into the slots causes the fretboard to bow. The fret slots must be cut at a precise 90 degree angle to the centerline of the fretboard. And, the distances between frets must also be precise: measured to the thousandth of an inch. You can’t really mark these with a pencil – the line would be several thousandths of an inch thick. So, I am using an x-acto knife to mark the locations of the fret slots.
But, I am getting ahead of myself. First, the fretboard gets cut to size. It is narrower at the top and widens as it goes toward the body. I built a jig to cut each side of the fretboard to the proper angle.
Next, I measure the 29 fret positions with a digital caliper, which has an accuracy down to thousandths of an inch.
Finally, the slots must be cut precisely. I made a box with a sliding piece that holds the tapered fretboard in the proper position, centered in the box. The saw has a “stop” affixed to the side to blade that controls the depth of cut. And I embedded two rare-earth magnets into the box to hold the saw in a vertical position as I cut the fret slots.
As soon as the board is marked with 29 little cuts, I will start the process of cutting the slots.