blades are chattering on one side because its adjusted too much on the left or right, if you look at the blades, at the ends were they are attached into the body , you will see springs on a axle. comming up at each end of the blade drum , there will be a nut/screw ajuster , on each one , that will pull the base plate, up too, or push it away from the blades, you ajust them. till your happy , if you go to u tube"wes site and type in your model you will see a flim on it .
irish paddy
September 2010