Hi,

 I have modeled an enclosure with a front shell and a backing cover plate. The cover plate shape was based on a surface offset of the main shell, so the dimensions of the two mating surfaces are currently equivalent, which I anticipate will cause clearance issues. I am wondering what the best way is to subtract a slight amount of material from one, the other, or both surfaces to make mating more practical. 

 FWIW, this is just a proof-of-concept type exercise using generic dimensions. I am studying SolidWorks through an online course, but I got enthusiastic and tried to do this project on my own. If I can muddle through an entire workflow for this example, I will begin again with a specifically dimensioned model, using everything I learned.

If I need to drop back and fix something at an earlier stage in the stack, it's a great time for me to learn about it. 
 

Here is a rough breakdown of how I made the back plate match the mounting lip on the enclosure:

Select the face of the mounting lip countersink

Surface Offset

Body Delete/Keep 1

Insert Boss/Base Thicken the face

Offset on Surface

Extrude

etc.

I will appreciate any help you may offer.

Win 11 Pro and 2026 SolidWorks desktop install for Makers
 

Thank you!