The worm gear in {TAIL ~ the second housing} has {HEAD ~ a central hub} and to which is attached a support carrying the work head 
The worm gear in { TAIL ~ the second housing } has { HEAD ~ a central hub } and to which is attached a support carrying the work head
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH