The auger flights are formed from a flange that is helical around {TAIL ~ the central shaft} and {HEAD ~ the direction} of rotation of the helix may reverse at a selected point on the tube 
The auger flights are formed from a flange that is helical around { TAIL ~ the central shaft } and { HEAD ~ the direction } of rotation of the helix may reverse at a selected point on the tube
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH