This is my version of the wire grippers you can get to hold two wire together while you solder them.

Printed in PLA at 0.3 layer height. I blocked supports everywhere except for two small supports at the ends of the internal slots, these were easy to remove with a pointed tool of some kind. I also thickened the base of the push rods to make them less fragile.

I used springs that I happned to have left over from a kit, they were about 9mm diameter and 36mm long.

The cover caps intentionally stay proud of the body but could be cut shorter to make them flush.