Originally Posted by
onehundred80
I guess the drill is to clear a 6mm screw then if so a US standard letter B or C drill would have been fine, why make things more awkward?
No, there are 4 "thread-serts" or whatever you wish to call them that you use a rivet-gun to permanently affix to the large plastic cover on the Crossfire. So you are drilling the holes to accommodate the outside-diameter of the threaded-inserts, which then take a 4mm screw (also included with the Windstop). But the outside diameter of the threaded-inserts is 6.1mm. All this is specified in the installation instructions that come with the part.
If you wish I'll take pictures of it today.