Sunday, October 08, 2017

Why your SawStop riving knife still isnt aligned

My SawStop PCS tablesaw has a pretty fussy riving knife adjustment system. You have to crank the blade up to check alignment and then crank it back down to be able to adjust the bolts and of course every time you tighten the bolts you move the knife out of alignment. So back and forth you go crank, loosen, align, crank, tighten, crank, loosen, align,... Then once you’ve got it just right, and you crank the blade back down to a reasonable height to cut some 3/4” plywood the knife seems out of alignment. What gives!?

Turns out that the knife holder isn’t exactly tilted in the same plane as the saw blade. It’s off by the slightest half of a degree. That doesn’t sound like much, but when the difference between the kerf and the riving knife is measured in .001”, that’s huge. If you have this problem it will seem like either you have to push harder to push the workpiece past the riving knife or the workpiece seems to want to drift away from the fence and cause burns along the cut. I had the latter problem. SawStop surprisingly has no mechanism to adjust the tilt. What I did to fix this was to add a couple of pieces of tape as shims to tilt the knife in the opposing direction as in the photos below.

Adding blue tape to the upper clap area
Adding blue tape to the lower clamp area on the opposite side