Since the P2 ships without a gearbox, I’ve got to make one. I did some basic math to work out impeller speeds and motor speeds needed, then decided a 1:2 gearbox on the P2 would be suitable, then a 1:1.8 to 1:2.5 from crank would do the rest if needed.

I ordered a T5 36 tooth timing pulley and a 300mm belt to suit. The belt is a cheap one, just to prove the design, but will eventually be replaced with a high quality Gates belt.

Quick ‘dummy’ fit to give me some idea of how it fits together and it will allow me to transfer that into CAD.

I found that the 6004-2Z bearings were sufficient for the job, being able to handle 30000rpm+, handle the appropriate loads and were affordable (~$13ea).

I bought two for the input shaft and two for spares.

Knocked up this quick design, it will more then likely change as I find out things don’t fit, need tweaked or changed.

Started to 3D print a test, but it failed about an hour in. ~250mm diameter ABS prints are a bit tricky to stop warping, so will switch to ABS for the next go.

Till next time!