The prototype came out WONDERFUL, we tested it with some of the generic PVC tubing I had lying around, and it was able to actually draw fluid! Although twisting it with your fingers is not easy...; The double herringbone design works extremely well, I tested two different versions, one with a 22.5 degree herringbone and one (pictured above) with a 45 degree herringbone. The 22.5 degree herringbone is easier to print but doesn't provide the same degree of "tightness" that you get with the 45 degree, it's very easy to push the gears out of the 22.5 degree one, whereas the 45 degree one it's nearly impossible. But the 45 degree one has a lot of curling on the top of the gears, and I can't accept that.

I'll probably do one last iteration of the design before adding in the housing and gears and try 33.75, my idea is that this will give a nice balance between the two. Speaking of the housing and gears, lets take a look at that.

The housing basically consists of a mounting plate for the GM23 motor, and a couple of gears to drive the pump. The outer gear on the pump will get attached directly to the plate. The large gear is screwed into the pumps drive gear, and then turned by the GM23 motor. This design should be 3D printable on any printer, without supports!

Once I've verified the design works, the final step will be just adding a small housing on the other side to cover the motor and pump internals, then it'll look nice and snazzy!