A friction testing machine and method for measuring {HEAD ~ friction characteristics} between {TAIL ~ a test sample} and a friction surface 
A friction testing machine and method for measuring { HEAD ~ friction characteristics } between { TAIL ~ a test sample } and a friction surface
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH