A very significant amount of tolerance is allowed for {HEAD ~ the fit} between {TAIL ~ the blade} and the slot, thereby reducing the cost associated with highly accurate 3 D joints 
between
A very significant amount of tolerance is allowed for { HEAD ~ the fit } between { TAIL ~ the blade } and the slot , thereby reducing the cost associated with highly accurate 3 D joints
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH