Digital Designs and Scientific Hardware - Open-Source Lab: How to Build Your Own Hardware and Reduce Research Costs - page 231

fuge should deliver over 4,400 g , more than enough to spin down bacterial cells. The Dremel-
fuge has surprisingly competitive technical specifications, when used on high-speed Dremels.
For example, at 16,000 RPM, Dremelfuge matches commercial centrifuges. It can do better. If a
Dremelfuge is used with a Dremel 300, a maximum speed of 33,000 RPM equates to a force of
over 50,000 times earth's gravity, which puts it into so-called “Ultracentrifuge” territory. The
latest version (as printed by Shapeways 72 ) has successfully spun tubes at this speed.
Obviously, the Dremelfuge is a potentially hazardous tool and significant safety considera-
tions and common sense are necessary when using it. 73
The general steps for making and using a Dremelfuge are the following:
1. Print the Dremelfuge chuck on a RepRap or buy Dremelfuge preprinted from a 3-D printer
supplier. When printing, use the maximum infill for strength and stability.
2. Atach the Dremelfuge chuck securely, either by tightening a chuck securely or screwing a
rotary tool disc holder securely to the center of the Dremelfuge.
3. Seat your drill or rotary tool so that Dremelfuge's shaft/axle is vertically oriented. You can
do this using conventional building materials, OpenBeam (as was discussed in the begin-
ning of this Chapter) or Makerbeam, or even conventional chemistry setups. Then, place
the drill/tool with the Dremelfuge into a metal chamber (e.g. a metal cooking pot) for safety.
Wear eye gear and other appropriate personal protective items to protect yourself in case of
disintegration.
4. Start at the lowest speed and ramp up the RPMs. Do this irst with no tubes or loads atached
and test the Dremelfuge for safety at the speeds you intend to use it.
5. Once proven safe at the intended speed, you can start to test and use Dremelfuge under
load, that is with desired size of the lab samples and perhaps water. Once this is done, move
to the lab samples. Make certain at all times that identical tubes or columns are used, with
identical amounts of fluid or mass on either side to maintain balance. Always balance the
Dremelfuge or accidents may result .
6.5.2.2 Microcentrifuge
If you are willing to trade a litle performance for a very low-cost centrifuge, consider the
table-top microcentrifug e 74 (shown in Figure 6.73 ) developed and open-sourced by Thingi-
verse user Tinytim.