The joys of parts with not friendly printing geometry. There’s another cylindrical recess running at 90 degrees to the one that’s visible in this photo.
Apologies for the very obvious layer lines. Harsh direct overhead lighting makes them a lot more obvious. The prints are much better in person, I promise.
Edit: Finished part showing the second cylindrical recess. They’re both dimensionally important, which is why the parts weren’t printed flat.
45° is a great cheat code for overhangs assuming you can keep the parts on your bed.
Also less likely to crack under the pressure of a reciprocating slide, since they usually crack along layer lines.