Quote Originally Posted by irving2008 View Post
If these are front and back surely your tolerances must be a bit tighter than +/- 1mm if you want them to match up? 0.1mm more like it!
Its not absolutly paramount that the front and back are spot on except the holes, the holes have to match up but the casings can be out as much as 2mm as nothing pretrudes between them or anything.