I just bought an 8hp craftsman wood shredder/chipper at a yard sale. It starts, runs well, etc. The problem I'm having is that it doesn't chip very well, if at all. When I try to feed branches in (we're talking 1" stuff, this can handle up to 3"), the branches vibrate like crazy (painful to hold) and don't want to go in.
I took the chutes (has two chutes, one for twigs and small branches, one for branches up to 3") off and the blades on both sides seem sharp (not like pocket knife sharp, but they will cut you if you run your finger along them and press hard), the flails move freely, and I can't see anything wrong.