In one aspect of the invention, a degradation assembly has an attack tool
with a body and a shank, the body having a wear-resistant tip. The shank
is disposed within a bore of a holder secured to a driving mechanism. A
washer is positioned in-between the attack tool and the holder and fitted
around the shank of the attack tool, wherein an outer edge of the washer
has a hardness greater than 58 HRc.