In HC28 Hydraulic Rock Drill (or Hydraulic Drifter) operations—especially in dusty mining environments like surface quarries or underground tunnels—the Shank protection 86778644 (dust cover) acts as the “first line of defense” for the drill’s shank connection. The shank is the critical link between the drill and the bit, and even small amounts of dust or rock chips entering its connection can cause accelerated wear on threads, jamming during rotation, or damage to the transmission system. With over a decade in mining equipment maintenance, I’ve seen generic dust covers fail quickly: most use thin, brittle plastic that cracks in 1-2 months of heavy use, or loose-fitting rubber that can’t block fine dust. This leads to frequent shank replacements (costing $800+ each) and unplanned downtime of 1-2 days per incident.