Cathal has designed a simple centrifuge using open source hardware technology, and you can order one yourself! (For use as entertainment purposes only, of course; wouldn’t want anyone to save nearly a thousand dollars by not buying real centrifuge now would we?)
Dremelfuge is a rotor designed to fit standard lab microcentrifuge tubes and miniprep/purification columns, to be spun by either a powerdrill or other
chuck-loading machine or by a popular rotary tool.
Dremelfuge features an easy click-in loading system which holds tubes
parallel to the plane of rotation for optimum pelleting and delivery of
force.
Intended basic applications of Dremelfuge include column purification
(tested to work with miniprep columns) and bacterial/cell debris pelleting
(under testing). With standard microcentrifuge tubes, the average rotary
distance is 4cms. Results (below) are shown with the Dremelfuge used to pellet E. Coli samples:
E. Coli sample pelleted with Dremelfuge
Dremelfuge is open-source hardware. Source files are available on
Thingiverse, linked from the items on Shapeways. The Creative Commons
license used entitles copying, sharing and remixing for any non commercial
purpose. Please consider that professional printing services qualify as
commercial use.Two editions of Dremelfuge are available for purchase at
www.shapeways.com/shops/labsfromfabs
DIYbio 
Put it on instructibles!
Dude. Forget competing with microfuges – I can buy one used for $150 anyway. But 50Kg is entering into ultracentrifuge territory. That’s higher than the old Sorvall Superspeed goes.
How high could you go, if you got a more powerful drill and attached it to a standard Sorvell or Beckman titanium rotor? Would gyroscopic effects keep it stable?