The head is shaped to define {HEAD ~ a channel} for receiving {TAIL ~ an exposed margin} or flange of a hinge mount to rigidly engage the hinge 
The head is shaped to define { HEAD ~ a channel } for receiving { TAIL ~ an exposed margin } or flange of a hinge mount to rigidly engage the hinge
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH