When the abrasive surface contacts {HEAD ~ the exterior surface} of {TAIL ~ the work piece}, it does so in a direction that is transverse to a longitudinal axis of the work piece 
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When the abrasive surface contacts { HEAD ~ the exterior surface } of { TAIL ~ the work piece } , it does so in a direction that is transverse to a longitudinal axis of the work piece
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH