Lockable bench dog for 20mm holes

As I am a woodworker too I had a need for a lockable bench-dog. In the past I made them from 20mm wooden rods but that was a lengthy job, mainly cleaning the lathe again, and they have the problem to be pretty loose with low humidity and stick when it's humid.
Quick design in Tinkercad, 59mins of print time, an M6 nut and Epoxy glue, done. Instead of Epoxy superglue gel works fine too.

Most likely this will also work with 1/4" bolts and nuts. The 45° planes should be sanded lightly to make the parts glide smoother.

Print Settings

Printer brand: Anycubic i3 Mega S

Supports: Yes

Resolution: 0.3mm

Infill: 25% Cubic, dual line

Filament material: used PLA but others will work too