It was a bit of a job to install, the existing nut on the spindle thread seemed a bit too small for the new spindle thread (maybe you guys could supply a new nut with the spindle?). But got an engineer friend to help. When fitting the cutters, I would place 4 on at once, then hand screw the 4 bolts, then use a drill close to tight, repeat for the whole row, then I would go over the whole row screwing by hand tight, backing off a little then fixing on hard. This helped them centre themselves. I then went over all 56 cutter heads, which was good because 2 weren’t hard tight. Once installed super impressed with the result. Didn’t have to adjust the blades at all, amazing how the machine cutting is not much louder than when it’s just spinning now. No machine marks at all, still the same snipe at the start and end of the boards but that has more to do with the machine/rollers than the cutter head. Would definitely recommend, turn your $1000 machine into a $2500 machine for much less $$.