Wood chipper repairs - part 1: knife sharpening

Today, we have the 5 hp MTD wood chipper / shredder (242A645-515) in the garage. The wood chipper is jammed, the blades are dull, and the roof needs some holes fixed. Should have been a one day project, but project creep kicks in and it takes 3 days. This is part 1. We get the knifes removed, sharpened, and reinstalled before we find a couple of nasty surprises that take another full day to fix, but that is part 2. In part 3, we get around to fixing the holey roof.