plane ▁or ▁prior ▁position ▁G 7 3 , ▁G 7 4 , ▁G 7 6 , ▁G 8 1 - 8 9 = ▁The ▁function ▁to ▁perform , ▁for ▁example , ▁G 8 4 ▁spec ifies ▁a ▁right - hand ▁t apping ▁cycle . ▁X = ▁Position ▁of ▁hole ▁or ▁pocket ▁in ▁X ▁axis ▁ ▁Y = ▁Position ▁of ▁hole ▁or ▁pocket ▁in ▁Y ▁axis ▁R = ▁Z ▁axis ▁start ▁position , ▁also ▁known ▁as ▁the ▁ret ract ▁plane ▁or ▁" R - plane ". ▁P = ▁D well ▁time ▁( in ▁mill iseconds , ▁where ▁applicable ) ▁Q = ▁Dep th ▁of ▁each ▁pe ck ▁( G 7 3 , ▁G 8 3 ) ▁or ▁amount ▁of ▁shift ▁for ▁b oring ▁( G 7 6 , ▁G 8 7 ) ▁I = ▁Sh ift ▁amount ▁in ▁X ▁direction ▁J = ▁Sh ift ▁amount ▁in ▁Y ▁direction ▁Z = ▁Sh ift ▁amount ▁in ▁Z ▁direction ▁( N eg ative ▁because ▁cutting ▁is ▁done ▁in ▁negative ▁Z ▁direction ) ▁F = ▁Fe ed ▁rate ▁ ▁H = ▁Fe ed ▁rate ▁for ▁finishing ▁cut ▁S = ▁Sp ind le ▁speed ▁L = ▁Number ▁of ▁cycle ▁repet itions ▁M = ▁Mis cell aneous ▁functions ▁A , ▁B , ▁C ▁and ▁D ▁are ▁used ▁for ▁Rect angular ▁pocket ▁mach ining . ▁ ▁A = ▁Mach ining ▁allow ance ▁B = ▁Step ▁over ▁C = ▁Step ▁depth ▁D = ▁Add itional ▁depth ▁of ▁cut ▁for ▁first ▁pass ▁ ▁G 8 0 ▁is ▁used ▁for ▁can cell ing ▁the