Why do these walls have non-uniform slicing thickness that occurs in-line with cutout features?

[bbarham 0]

I am trying to print a simple coupler piece, however, when I slice it the inner hole diameter is not consistent. The incongruity occurs level with the side hole for the thread insert. I have the same problem with a bracket piece that has a side cutout for a rocker switch. Any ideas? I have been searching for a while and can't find anything on this. Thanks

 

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Bottom Cover^3800 MR Relay Fixture.STL Coupler.3mf Coupler_short^3800 MR Relay Fixture.STL

Edited February 6, 2023 by bbarham
Formatting

[MariMakes 203]

Hey @bbarham,

 

Welcome to the Ultimaker Community 🎉

I recognize your issue, it's related to your hole horizontal expansion. 
The parts of the cylinder where an O becomes a C are not expanded because they are not considered to be holes. 

Do you require the holes to be bigger? How important is dimensional accuracy for your model?  
Can you solve your problem in CAD or just with horizontal expansion?