Quote Originally Posted by Jonathan View Post
6mm cutters tend to be convenient if the thickness of the material is roughly 10mm or greater, so I tend to space parts out by 7mm. You can get away with a little less, but the finishing pass tends to work better if there's a reasonable amount of clearance.
On top of this make sure there's room or spacing for a Lead-in and lead-out or ramping etc otherwise it means plunging into material and person doing cutting wont thank you for that.!

Really your better letting the person doing the cutting setup the layout to suit there clampings methods and machine.? If you try to cut it too fine on material it's easy to get into trouble so better having a little extra for safety sake.