This repair is for one of our knobs/dials for our stove that cracked and could no longer spin the D-ring shaft on one of our stove burners.  Their is an internal metal liner that was able to spin freely after it cracked.

I originally was going to model the entire knob and attempt to fit a 3D printed part on the D-ring, but was afraid of the plastic holding up over time against the metal as well as getting my tolerances tight enough.

On Reddit, someone suggested I create a “collar” to brace the shaft and keep it from cracking again.  This worked perfectly!

It solves the eye-sore of a completely different looking knob on the stove from the others, it also re-uses the original metal liner to interface with the D-ring which I knew had factory tolerances that I couldn't achieve easily.

If you have issues with getting it to work for your particular knob, let me know.  You may need to scale up/down to fit your specific application.

Internal Diameter: 12.9mm

Outer Diameter: 16mm

Depth: 6.5mm

Internal chamfered edge on one end to help with pressing on to the shaft, just add some glue (I used super glue) and press on.

Fast print time: ~5 mins

Print settings basically don't matter because its so small, infill % doesn't matter as long as you have 2-3 perimeters/walls.  I used a layer height of 0.2mm, but smaller/larger could do the trick as well.