Created clip test leads from paper clips, salvaged molex connector, salvaged springs.
Spring used: ID: 5.5mm, OD: 6.3mm, Length: 21mm - Molex connector salvaged from an old PC power supply - Black plastic tubing(salvaged from an old vehicles windshield washer fluid lines): ID:3.2mm, OD: 5mm, Length cut: about 16mm (could be purchased at any auto parts store).
Detailed video of build: https://www.youtube.com/watch?v=cGHGMCx4kXY

Printrbot

Simple Black

No

Yes

.2mm

15

Printed both parts upright...used support for the tip only.