The presetting device 14 must be adjusted by turning the knurled thumb {TAIL ~ screw} 16 to perform {HEAD ~ the calibration} 
The presetting device 14 must be adjusted by turning the knurled thumb { TAIL ~ screw } 16 to perform { HEAD ~ the calibration }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD