US Patent 10107098 Bore wear compensating bit holder and bit holder block

A bit assembly includes a base block and a bit having a forward body portion and a shank. The bit includes a diametrically expanding retainer circumferentially disposed around a shank of the bit adapted to maintain the interference contact between the bit and the base block as the diameter of a bore of the base block increases from use. The bit assembly also includes a sealing gasket that forms a force fit between a washer disposed about the shank of the bit and the base block.