The shim is then formed to include a feature on {HEAD ~ its surface} which complements {TAIL ~ the surface profile} of the assembly surface 
The shim is then formed to include a feature on { HEAD ~ its surface } which complements { TAIL ~ the surface profile } of the assembly surface
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH