Verified by Rachel Mayfield, Supply Chain Analyst - August 2026
Typical coefficient of friction ranges for common material pairs, static and kinetic, dry and lubricated. Read the ranges as indicative: published friction values scatter enormously because surface finish, contamination, humidity, pressure and speed all move the number, often by a factor of two. This chart is for orientation and sanity checks. It is NOT design data - for anything safety-related (brakes, clamps, lifting), test the actual pair or use the component manufacturer's certified figures.
Coefficient of friction by material pair (typical ranges)
| Material pair | Static, dry | Kinetic, dry | Lubricated |
|---|
| Steel on steel | 0.5-0.8 | 0.4-0.6 | 0.16 (oiled) |
| Steel on cast iron | 0.4 | 0.23 | 0.13-0.2 |
| Cast iron on cast iron | 1.1 | 0.15 | 0.07-0.1 |
| Brass on steel | 0.35-0.5 | 0.44 | 0.19 |
| Aluminium on steel | 0.45-0.6 | 0.47 | - |
| PTFE on steel | 0.04-0.1 | 0.04-0.1 | 0.04 |
| Nylon on steel | 0.3-0.4 | 0.3 | 0.12 |
| Rubber on dry concrete | 0.6-1.0 | 0.6-0.85 | - |
| Wood on wood | 0.25-0.5 | 0.2-0.4 | 0.2 (wet) |
| Steel on ice | 0.03 | 0.01-0.02 | - |
How to read friction values
Static friction (breakaway) exceeds kinetic (sliding) for nearly every pair, which is why things lurch when they start to move. Lubrication collapses the differences between materials: most oiled metal pairs land near 0.1-0.2 regardless of what the dry values were. PTFE is the exception that behaves as if permanently lubricated - the reason it lines bearings, gaskets and low-force slides.
Where this matters in component selection
Bolted-joint clamping calculations assume a thread friction coefficient (typically 0.10-0.16 lightly oiled) - it is why the same torque produces wildly different preloads on dry versus greased threads, and why our bolt torque chart states its lubrication assumption. Linear guides, clutches and brake materials are specified from certified friction data, not generic tables.