Metric measurements.

Hi folks

This is my first posting to the group, in the hope that someone will
be able to assist me.

I create my CAD drawings with TurboCAD. For several years, I have
produced my drawings using metric (mm) measurements. Before I
started experimenting with CNC, if I printed the drawing full size,
then it was printed almost exactly the size of the item (within the
accuracy of the printer).

To use the drawing to create a toolpath for the CNC cutter, I export
the drawing initially as a .dxf file. I have then converted the
file to G-code using two programs - KCam or Simsoft Mach 2. Both
of these will produce a G-Code script. I then use the software to
drive the CNC controller. At present, because I am driving my CNC
control with KCam on an old laptop under Windows 98 (Mach 2 requires
WinXP.) However, I have found a problem. The CNC driver seems to
work in imperial units (inches). Hence, a component that should be
say 20mm long, becomes 20 inches long. This is a little difficult
on a milling machine which only has around 12" of travel.

In the KCAm Setup/Table Setup menu, it asks if you want (are using?)
imperial or metric measurements. However, choosing metric in this
dialogue box does not appear to make any difference to the finished
size of the article.

Does anyone with experience of these programs - Mach 2 or KCam know
how I can set them up so as to convert metric .dxf files to metric
machine codes?

Thanks

Keith