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(Code to do a thread at starting at 0,0,0) 
(Assumes bottom of tool starts at top surface of material)
(#1 is centerX #2 is centerY)
(#3 is Z depth -- bottom)
(#4 is tool diameter)
(#5 is thread major diameter)
(#6 is feed rate #7 = thread pitch)

o3810 sub
(#10 is radius of tool center)
(#11 = ToolRadius)
#11 = [#4/2.0] 
(#12 = BoreRadius)
#12 = [#5/2.0]
#10 = [#12 - #11]
(#17 = CurZ)
(#14 = Z per turn)
#14 = [1.000/#7]
(cut out to edge)
(#15 is X #16 is Y #17 is Z)
#15 = 0 #16 = [#10]
G0 Z.2     (get clear of the metal)
G0 X#1 Y#2 (go to the center)
G0 Z[0-#3] (drop to the bottom)
G1 F#6 Y[#2+#10] X[#1+0]  (Go to edge)
G3 J[0-#10] I0 Y[#2+#10] X[#1+0]  (Go around the loop)
#17 = [0-#3]
o3813 while [#17 LT 0]
    #17 = [#17 + #14]
    G3 J[0-#10] I0 Y[#2+#10] X[#1+0] Z[#17] (Go one turn)
o3813 endwhile
G01 X[#1+0] Y[#2+0] (back to the center)
#100 = 0 (signal no error)
o3810 endsub

(#1 is centerX #2 is centerY)
(#3 is Z depth -- bottom)
(#4 is tool diameter)
(#5 is thread major diameter)
(#6 is feed rate #7 = thread pitch)
g0 z.2
g0 y-1.5 x-3.0 (move to empty place)
g0 z0   (Down to the surface)
m5 m0 (msg, change to vee threading tool)
g0 z.2
g0 x-1.5 y-1.5 (back to the center)
g0 z0   (Down to the surface)
s2760m3 (Start your engines)

o3810 call [-1.5] [-1.5] [1.330][.750] [1.0] [5] [8]  (The cap threads)
g0z.2
m5

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