Edit (22/10/2014): Cleaned up the design a bit and added some extra squeeze on the wheels to leave more room for tension. I found a lot of the mini v wheels to be out of spec, causing vibration and noise in the bearings which resonates through the whole frame, so I'm switching over to solid v-wheels. New design coming very soon! This 2020 v-slot carriage mount truck is a modification of Steve Graber/brandonh's Carriage for Kossel / Mini Kossel.  These have been tested and work beautifully on OpenBuilds 20 x 20 mm V-Slot Extrusion with Mini V Wheels and will most likely work with all other 2020 extrusion as well (let me know in the comments if it does). Use an M3 50mm SHCS or other machine screws for the tensioner.   2020 V-Slot Aluminum Extrusion: http://openbuildspartstore.com/v-slot-20-x-20mm/      Mini V Wheel Kit: http://openbuildspartstore.com/mini-v-wheel-kit/   Credits go to brandonh and Steve Graber for the original designs!  Pics are of an early prototype, ignore the extra mount hole. I'll upload new pics when I get the new version printed. I also hacked up a Rostock style, printable universal joint carriage to work with this or any other 20mm x 20mm mounting grid carriage roller base: https://www.youmagine.com/designs/rostock-style-printable-u-joint-carriage-for-kossel-mini-kossel