I got a used WW Grinder Renegade 250 and the blades on it were dull. The branch chipper blade was relatively easy to get to. Just take the bolts off the funnel feeder tube. The bolts are all exposed. The blade is held on with allen head bolts, but you can hold the allen head secure, then turn the bolts on the other side with a box head wrench to make it easier to turn.
I had lots of trouble with the chipper blades, but I was successful in turning them around to the sharp sides. There's 4 corners you can use before they need to be replaced or sharpened. First tilt the machine backward so the bottom is exposed, then take the lower screen off. This model has 6 free spinning blades on each of the 3 rods. On the right side of each rod is a sleeve with a hole with a hollow-bushing pressure fit to keep the rod from sliding out. Mine was not easy to see because it had debris covering the hole. The hole is 3/16", so I used a 5/32" punch to push it out, then the sleeves and blades can come out and turned around to the sharp edges. One side has a larger hole than the other. Hammer the punch from the small hole out of the larger hole. It wasn't easy for me to get the bushings out because I broke 2 punches in the process. I spent $15 on punches, but a local lawnmower repairman quoted me $70 for him to do it. I got off cheaper plus I learned how to do it for next time!
Now that I see how well it's made, you can see that it's made for years of hard work.
Edited by WagonBill, August 02, 2016 - 02:58 AM.