Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2805225.

Small part for repairing my broken scissors. The core part which fits inside the scissors is 7mm diameter, 6mm across flats, and height is 4.8mm. To suit screw outer diameter 4mm (the central hole is 3.5mm so the screw self taps).

Update: I printed this in Feb 2018 using PLA, and the repair is still good in Sep 2020, even after putting them through the dishwasher a few times. It's proving surprisingly strong!