a blade hammer on a root portion of {HEAD ~ said blade} engageable with a blade support to position {TAIL ~ said blade} in the run condition, and 
a blade hammer on a root portion of { HEAD ~ said blade } engageable with a blade support to position { TAIL ~ said blade } in the run condition , and
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH