Convert hole patterns from DXF file to G-Code

I recently needed to generate some odd hole patterns for drilling sheet metal and have written a small python program to read a dxf file and convert it to g-code for my sherline mill.
The holes must be circles and be on the holes layer (case is not important e.g., Holes or HOLES be OK).
Attached are the program plus a sample dxf along with the resultant ngc file.
I only use this for single hole sizes but if there are differing hole sizes it will split the code into sections of hole sizes but there is no tool change code (you could insert this manually in the output text box then save the file again).
Cheers, Phill

I had a project similar to yours, I import the holes from a dxf layer and convert it to a g83 drilling cycle. Tool number,feed,speed can edited on a xml file. I made this because the machine that I used (hurco vm2) uses a different g83 syntax so it generates 2 files, one for the hurco and the second for linuxcnc so I can see the code preview and simulation.

How do you implement the graphical interface? it´s my next step

João

I used Tkinter...
wiki.python.org/moin/TkInter

Thanks, I do use polar coordinates in one of my NGCGUI routines.