Contact Materials	μs
Metal on ice	0.03-0.05
Steel on Steel	0.8
Steel on brass	0.35
Steel on graphite	0.1
Steel on teflon	0.04
Aluminum on aluminum	1.1-1.7
Wood on wood (dry)	0.3-0.7
Wood on wood (wet)	0.3
Leather on wood	0.2-0.5
Leather on metal	0.3-0.6