Ali said course will not clear the side panels.> I had a similar problem racking up an old Digittronics paper tape reader from the early 70s. The reader faceplate was a fairly thick piece of aluminum plate with recessed holes for the rack screws, and my modern server rack screws and captive nuts were oversize. The screws had to be recessed because the rear face of the stinless steel paper tape input and output hoppers were flush with the faceplate and latched on by sliding downwards to engage two flat-headed pins. In my case it was a simple job to chuck a few of the screws in the lathe and skim the heads down by 1 or 2 mm overall diameter, but it would not have been much more effort to put them in a an electric drill chuck and hold a file against them. If you can't find the correct ones perhaps you could try that approach. Steve.