In HC20 Hydraulic Rock Drill (or Hydraulic Drifter) systems, the Ring 86668753 (front guide bushing) is a “critical guide and protective component”—it fits around the shank to ensure stable reciprocation, while blocking mining debris from scratching internal parts like the piston or seals.

1. Wear resistance: Made of heat-treated alloy steel (HRC 45-50), it withstands long-term shank friction without premature wear.
2. Precision fit: Inner hole tolerance is ±0.003mm, ensuring tight fit with HC20’s shank—no looseness.
3. Debris protection: Smooth guide surface and tight fit prevent dust intrusion, extending internal component life.