Tightening Torque Table

hls tightening torque table

Size Pitch Reference tightening torque (N·m)
Concave (set) screw Convex (lock) screw Proof torque
M8 Coarse 10 ± 10% 10 ± 10% 16
M10 Coarse 18 ± 10% 18 ± 10% 30
M12 Coarse・Fine 30 ± 10% 30 ± 10% 52
M14 Coarse・Fine 30 ± 10% 30 ± 10% 52
M16 Coarse・Fine 70 ± 10% 70 ± 10% 120
M18 Coarse・Fine 70 ± 10% 70 ± 10% 120
M20 Coarse・Fine 100 ± 10% 100 ± 10% 220
M24 Coarse・Fine 170 ± 10% 170 ± 10% 370
M30 Coarse・Fine 590 ± 10% 590 ± 10% 980
M36 Coarse・Fine 590 ± 10% 590 ± 10% 980
Note: The concave (setting) screw can be tightened to the torque required for the target application (low or high)

Installation procedure and handling precautions

  1. Tighten the concave (setting) screw with the torque required for the application, the convex (locking) screw requires to be tightened to a specified torque set by our company. → Tighten the concave (setting) screw with the torque required for the target application. The convex (lock) screw must be tightened to the Hardlock specified torque.
  2. Please refrain from using improper tightening tools (wrong size and/or worn-out ones). If you are using improper tools, there is a risk of damage during tightening. → Refrain from using tools that are the wrong size, worn out or otherwise improper. Using such tools may result in damage during tightening.
  3. The HLS should not be welded. Doing so reduces the screw strength.
  4. Do not apply surface treatment or coating without guidance from Hardlock. The HLS is heat treated, and surface treatments may cause degradation in strength or hydrogen embrittlement.