G0 is a rapid traverse, you don't specify a speed, just where it should go.
G20 is for inch mode, feeds will be in inches per minute.
G91 is incremental distance mode, you specify how far to move from the current location. You just calculated absolute coordinates so we want to use G90 for absolute distance mode.
Depending on your machine, you might need some other preparatory codes too like G17, G40, etc.
You would want to "touch off" your part with an edge finder to locate the spindle centerline on our (0,0) point. You can use a G54 work offset to specify where that is or in mach you can just click "Zero X" and "Zero Y" and it puts in the offset for you so it reads 0,0 at the 0,0 point on the part.
You will also have to set the Z axis zero. which can be done with a G43 tool length offset or you can just bring the Z down to the surface of the part and click "Zero Z" in mach.
Once you have your zeroes, you can start on the code:
Code:
G17 G20 G40 G90
G0Z1.0000 //raise tool to a safe level
M3 S10000 //turns on spindle clockwise with speed of 10,000 rpm you have to do this manually if your machine won't do this
G0X-1.8925Y-0.0005 //rapid to point A
G0Z0.0100 //rapid Z down near surface
G1Z-0.1000F20 //plunge .1 deep into material
G1X-2.6195Y-0.0005F60 //feedrate move to point B
G1X-2.6195Y-0.0320 //feedrate move to point C
G2X-2.6500Y-0.0625I-0.0305J0 // feedrate arc move to point D
G1X-3.2940 // feedrate move to point E
Keep going from there. A few notes:
You do not need to specify a feedrate on every line. Once you specify it, the control will assume you want to use that feedrate until you tell it a new one.
It is probably a good habit but you do not need to specify coordinates if they do not change. ie don't add a Z coordinate to every G1 line if it does not change.
I and J are the incremental distances from the current position (point C above) to the center of the arc. We know from previous calculations that the radius is .0305 and we see from the drawing that the center is -.0305 in X away from point C and at the same position in Y. SO I should be -.0305 and J should be 0.
Matt