1/16 Scale FrankenDiff

[Zabco]

All educational opportunities, best way of learning. Strange though the way your slicer is doing scaling. I use Cura or PrusaSlicer, which is forked from slic3r, depending on which printer I am going to use and have never had that issue. When I size a cavity in one of my designs that's pretty much exactly what I get in the final print.