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