Fully-printed Festool 20mm dog hole clamp system

I liked the look of UltiArjan's low profile clamping system but wanted something fully-printed that works with plain 20mm dog holes.

It took some work to get it clamping hard and releasing easily, but I think I'm there!

If you just want to "kick the tyres", then a short spreadbolt, a spreadclamp, a couple of o-rings, and a nut will let you play around. You can even use a metal M12 nut if you have one to hand.

Note that for licensing reasons, you'll need to get the knob from here. https://www.thingiverse.com/thing:2856279

Video showing how it all works.
https://www.youtube.com/watch?v=_TA4Ls0p2zI&feature=youtu.be

(And yes, I could have just grabbed that shorter clamp bar rather than moving the stepblock back, but that's what happens when you try and talk and think at the same time!)