In general, a friction test machine according to the invention comprises a sample holder configured to hold {TAIL ~ a sample} in frictional engagement with a friction surface, and a motion device for effecting relative movement between the friction surface and {HEAD ~ sample holder} in a first direction 
In general , a friction test machine according to the invention comprises a sample holder configured to hold { TAIL ~ a sample } in frictional engagement with a friction surface , and a motion device for effecting relative movement between the friction surface and { HEAD ~ sample holder } in a first direction
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH