# Thread: G-Code Question, polar offset and pocketing questions?

1. ## G-Code Question, polar offset and pocketing questions?

I'm learning to use EMC, and have a fair amount of experience with heidenhein as a background of my programing experience.
I've read most all of the EMC2 user manual pdf and didn't see any mention of offsetting to a polar location.
Is there a way to set a pole and execute a cycle at different polar locations? Such as a round bolt circle with four holes 6 unit diameter x0y0 bolthole center, first hole at x3y0 h0 or zero degrees, execute drill cycle, next at x0y3 or h90, execute drill cycle, x-3y0 h180 or 180 deg, execute, next x0y-3 or h270, execute drill.
I'm guessing I could do a g2/3 arc in air above the part, but finding the end coordinates when a print is in degrees isn't always so easy as the above example.

Is there currently a polar coordinate offset built into EMC? I'm used to using a G10 or 11 for such things.

Is there provision for pocketing in EMC g-code? Or should pocketing be performed with a plunge and then manual path boxing out to the pocket confines and finally using a g41/42 around the pocket profile?
Some of the feature work I want to do with EMC is triangular pockets in 4,5,6 units cut into small decorative flywheels.

Thanks for your suggestions in programing EMC.
Is there another good source for examples of EMC code and how it is used?

mike

2. I was just asking on the emc-users list about the possibility of adding the G79 code for pocketing circular pockets.

Jon Elson wrote some 'C' programs to generate gcode for both a rectangular pocket and a circular pocket and a program for generating bolt hole patterns. I have copies of them and they were available on his website (can't remember the name, something like picosystems).

NCPlot has macros for bolt hole patterns and circular pockets.

Alan

http://jelinux.pico-systems.com/

Nancygal

4. I found the programs, look like nice simple to use macros.
Can't wait to try them out.
Now about that offset polar, am I going to just need to put a 4th axis on my rotary table and repeat pockets around a wheel like that?
I'm asking all this b/c I'm looking ahead, I've got around \$1000 to spend, and was going to get pmdx/geckos/steppers for my bridgeport. Since EMC is open sourced, and I like linux anyhow I'm just seeing how featured it is.

http://jelinux.pico-systems.com/gcode.html

5. I should add that I downloaded the rectangle pocket exe file and used synaptic to retreive dosemu and freedos to run the dos.exe file from the site and it looks to put out very quality g-code.
Thanks for the tip.
Mike