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