Curator's Choice: A Selection of Instruments from the Museum Stores

Richard Paselk, Curator

Swinging Bucket Ultracentrafuge Rotor

I find this rotor to be particularly attractive due to its clean smooth lines. Is its aesthetic appeal due strictly to engineering, or did aesthetics play a part in design?

The rotor is machined from titanium with titanium buckets capable of a vacuum seal. It is mounted on its dedicated stand with one of its “swinging bucket” sample tubes adjacent to it. The maximum centrifugal force generated in this rotor ranges from 1.27–2.69 million gravities over the length of the sample tube. Rotors like this were commonly used to separate RNAs, Ribosomes, cell organelles, etc. in sucrose gradients via differential centrifugation.

Description

The image shows the rotor head mounted on its custom stand (the aluminum disk demarcates the rotor) with one of the vacuum sealed titanium tube shields next to it. The head measures 5.8" H x 6.5" W. It is labeled by stamped white lettering on the top of the rotor as an IEC rotor - 41,000 rpm Type NO SB-283 rotor, Cat. NO 488 (see top view image for identification numbers etc.). The head is machined from a single piece of titanium, with a small attached aluminum disk on the bottom for measuring rotational speed stamped S/N 488088: TH25 (see close-up image of disk and shaft bottom). The rotor is accompanied with six turned titanium shields with aluminum screw-tops sealed with o-rings to allow the contents (held in plastic "test" tubes) to be maintained at atmospheric pressure while the rotor spins in a vacuum. The centrifugal force generated in this rotor at top speed (41,000 rpm) ranges from 1.27–2.69 million gravities. This rotor was used by the Biology Department at HSU for research and instruction c.1980 - c. 2000.

© R. Paselk 2013, Last modified 3 January 2021