1. Our Serrator bits are cut with a 25/1000 distance between the peaks (points). That equals 80 serrations per inch if you count peaks and valleys or 40 serrations per inch if you count only peaks. This aligns perfectly with the serrations on new brushes advertised as 56 serrations per inch. Go figure. I know a true 56 spi is 18/1000 between peaks.

2. Cutting serrations is not perfect. Don't expect perfect. Depending on the brush compounds and the amount of graphite in the brush the graphite will sometimes come loose on the serrations. I'm talking about little bitty pieces that can only be seen with a jewelers loupe. On a scale of 1 to 10, I would rate the cut at 8 to 9.

3. Re-shaping a brush from standup to laydown or laydown to standup is easier with the full face shaper. What happens is the brush serrations will bottom out once the center of the brush is serrated and the peaks on the brush start hitting the valleys of the cutter. Re-shaping can be done with the serrator, it just takes longer. We spent a lot of time finding the best compromise between cut quality and speed with cut quality being the main priority.

4. Serrations are cut by installing the FussyBrush main shaft with the appropriate bit size. Put a pinion on the shaft and rotate slowly while applying some pressure to the brush with a screwdriver or hex wrench. You can feel the cut being made and as it finishes the cut the feeling gets smoother. Kind of a touch thing. Like setting a pinion. Not hard at all but you do want to practice on some old brushes first.

5. Re-serrating is easy. Just make sure you keep your brush in the same position. I always keep my shunt wire on the bottom so the spring fits on top over it.

6. The cut diameter of the serrator bit is determined by the valleys on the bit, not the peaks. The valley of the bit is the point on the brush. If you measure the outside of the a 300/1000 serrator bit it will be +- 340/1000. That is because the serrations are cut 20/1000 deep, thus leaving a radius of 300/1000 after subtracting 2x20/1000 from 340/1000.