Harvey,
this is my "CNC PCB drill". It's my 2400 x 1500 plasma cutting table. Well it's all I've got LOL:
PCB DRILLING ON PLASMA TABLE
Bertho,
thanks for that. You know what, I had to calibrate the axis when I built the table but today it would never have crossed my mind to do that. Thanks for the suggestion.
The next PCB, I'll simple adjust the photo positive bitmap image until it prints out exactly the same dimensions as what I get in the NC drill file. That way the board turns out the exact size it should be, not that a half mm over the entire length matters that much.
Cheers,
Keith.