{HEAD ~ The method} 9, further comprising resetting {TAIL ~ the reference position} to zero in response to an input command from an operator of the tool 
{ HEAD ~ The method } 9 , further comprising resetting { TAIL ~ the reference position } to zero in response to an input command from an operator of the tool
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH