Cause:
(1) blade wear, forming a hard layer of material between the roll and the rotor support plate
(2) V-belt tension is not enough
(3) hard material buildup behind the rear roll supporting plate, insufficient lubrication of the main bearing
Remedy:
1. Install new blade
2. V-belt tension
3. Clear the hard material, and lubrication of the main bearing until grease from behind the rear support plate emerge so far