The teeth project in the same direction as {HEAD ~ the flange} of {TAIL ~ the helix} to which they are attached 
The teeth project in the same direction as { HEAD ~ the flange } of { TAIL ~ the helix } to which they are attached
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