Hardlock Set Screw

The globally recognized HARDLOCK Set Screw

The HARDLOCK Set Screw is a revolutionary self-locking set screw (Hexagon socket head set screw) which applies the “wedge principle” and delivers superior self-locking effect like the other HARDLOCK products without any change in the current conditions of the application.


■ Very high self-locking effect.

Just like the HARDLOCK Nut, no matter the conditions the self-locking effect remains secure.

■ Possible to re-use

All metal with little abrasion, sustains a high self-locking effect.

■ Good and simple workability

Easy installation with commercially available tools.

■ Provides economic benefits

No retorquing work, no additional self-locking components such as adhesives etc. are required. The HLS provides significant cost reduction and superior self-locking effect.


Self-locking design


By combining the Concave Set Screw with its concentric conical depression (1) and the Convex Set Screw designed with an eccentric conical protrusion (2), due to the wedge principle they will lock themselves in the direction perpendicular to the axis.


The HLS has the same strong self-locking effect as the HARDLOCK Nut. The HLS with its “wedge principle” is ideal for preventing loosening from severe vibration and impact load, it can also be reused without reduction in performance.

Installation procedure


Tighten the Concave (set) Screw.







Use a general tightening tool (L-wrench or the like).







Then tighten the Convex (lock) Screw by hand. Make sure that there is a gap about 1 pitch between the Concave and Convex Screw before tightening.







Tighten the Convex (lock) Screw by the specified torque or by 1 turn (360 degrees)







Installation Complete






Tightening torque table



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.
  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.
  3. Refrain from welding the HLS (the strength of the screw will be reduced)
  4. Please do not apply surface treatment or coatings without our consent. Since the HLS is heat treated, depending on the surface treatment, it may cause degradation in strength or hydrogen embitterment.