The company I work for is just finishing the hardware and software for a
low cost CNC drill/mill machine for hobby use.  It won't have quite the
resolution of more expensive units but should be more than adequate for
most hobby boards.

My problem is I have to measure what it's useful resolution is so
prospective buyers can decide if it's adequate.  I imagine that for most
commercial systems you can calculate this by using the specifications for
all of the components and summing the worst case.

What I believe we need to do is somehow measure the resolution from test
boards, but I am unsure on how to do this.

The theoretical positioning accuracy when drilling is .001" +/- .0005
however I suspect in practice it is more like +/- .001

Routing is going to be much lower since the software can't compensate for
slack in the hardware as it can when drilling.

Any idea's would be appreciated.  The first model has a capacity of 8" x 12"
and uses a PIC17C756 to control the steppers and translate the CNC codes.
(I did the PIC code)

Thanks

Bob Bullock
KoolKits Electronics Ltd.
bobb@koolkits.com