I've been going over the Drawing that you've worked on (thanks very much for taking the time and effort!), but I'm not sure I understand what you did.
How did you combine the elements? How did you address all the errors?
davecoventry wrote: It may have something to do with grouping of objects which I did when I copied, mirrored and move some items as a group.
davecoventry wrote:@NormandC, thanks. The Compound option seems the way to go. I couldn't find the option at first, but it's in the "Part" menu.
NormandC wrote:Since FreeCAD is still missing the Assembly workbench, a Part Compound (from the Part --> Make compound menu) can serve as way to create an assembly of parts.