The knob 80 has an annular portion 82 arranged for frictional engagement with {HEAD ~ the exterior surfaces} of {TAIL ~ the rear wall} 66 on each side of the slot 76 
of
The knob 80 has an annular portion 82 arranged for frictional engagement with { HEAD ~ the exterior surfaces } of { TAIL ~ the rear wall } 66 on each side of the slot 76
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH