Power Lock Specifications
Materials, shaft range, torque capacity, clamping pressure and concentricity for MACHINING Force keyless shaft locking assemblies.
Precision-ground keyless locking
Every power lock ships to a documented material, shaft range, torque, clamping pressure and concentricity specification. Custom sizes and stainless variants are quoted to your drawing.
Body material
42CrMo4 alloy steel, C45 carbon steel, 304/316 stainless steel
42CrMo4 is the standard for high-torque industrial power locks; C45 covers lighter duty; 304/316 stainless is used for corrosive environments where standard steels would rust and lose clamping force.
Locking screw grade
Grade 12.9 alloy steel socket head cap screws with black oxide or zinc flake coating
Grade 12.9 screws are torqued to values published in the assembly instructions; anti-friction coating on threads and mating surfaces ensures consistent clamping force and prevents galling.
Shaft diameter range
6 mm to 600 mm depending on power lock series and configuration
Small assemblies (6-30 mm) suit encoders and instrument drives; medium (30-200 mm) covers most industrial gearboxes and pumps; large (200-600 mm) is used in wind turbines and mining drives.
Torque capacity
15 Nm to 1,800,000 Nm across the product range
Ratings assume a shaft surface finish of Ra 0.8-3.2 µm and a friction coefficient of 0.12; higher friction coefficients from surface treatment can increase transmissible torque proportionally.
Clamping pressure
100-200 MPa radial pressure on shaft surface under full torque tightening
The uniform 100-200 MPa clamping creates a shrink-fit connection that transmits torque through friction alone — with no keyway stress concentration and no fretting corrosion.
Axial load capacity
Typically 2-6× radial load, dependent on shaft diameter and surface friction coefficient
Because friction is the transmission mechanism, axial load capacity is proportional to shaft diameter and clamping pressure — much higher than a keyed connection of the same size.
Concentricity
0.01-0.03 mm TIR (Total Indicator Runout) when properly installed
Self-centering series achieve the lower end of this range; non-self-centering shrink discs may require indicator dial-in during installation to hit tight TIR targets on precision drives.
Shaft surface requirement
Shaft surface finish Ra 0.8-3.2 µm (ISO N7-N8), free of oil and grease
Excessively smooth shafts (Ra < 0.4 µm) reduce friction coefficient and torque capacity; oil or grease dramatically lowers friction — degrease shafts thoroughly before installation.
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