COEFFICIENT OF FRICTION TABLE FOR LEAD SCREWS (POWER SCREWS)


Typical friction coefficients of thread and collar in lead screws are given in the following Coefficient of Friction Tables.

Friction Coefficient [f] for Threaded Pairs
Screw Material Nut Material
Steel Bronze Brass Cast Iron
Steel, dry 0.15-0.25 0.15-0.23 0.15-0.19 0.15-0.25
Steel, machine oil 0.11-0.17 0.10-0.16 0.10-0.15 0.11-0.17
Bronze 0.08-0.12 0.04-0.06 - 0.06-0.09
Source : From Shigley's Mechanical Engineering Design [Ref 1] and Mechanical Design and Systems Handbook [Ref 2]




Thrust-Collar Friction [fc] Coefficients
Combination Running Starting
Soft steel on cast iron 0.12 0.17
Hard steel on cast iron 0.09 0.15
Soft steel on bronze 0.08 0.10
Hard steel on bronze 0.06 0.08
Source : From Shigley's Mechanical Engineering Design [Ref 1] and Mechanical Design and Systems Handbook [Ref 2]


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