For rapid settling of suspended solids from small quantities of liquid at speeds up to 2000 rpm. Hand crank, steel worm and bronze spiral gear are set at a ratio of 15 to 1. Longsweep crank is detachable and disengages when hand motion is stopped, allowing head to come to a gradual rest. Driving mechanism is completely enclosed and permanently lubricated in a one-piece cast iron body. Furnished with two metal shields, two 10 ml glass centrifuge tubes (one plain, one graduated). A screw clamp is provided for fastening to table tops of any thickness up to 1.75” (45 mm).