Patrick J. Hannan
Naval Research Laboratory Washington, D. C.
A
A Vibration-free Base
vibration-free base, ideal as a support for delicate instruments, can be assembled easily from readily available materials. It consists of three layers of l-in. plywood alternated with two layers of l-in. sponge rubber. As shown in the accompanying diagram, L/a-in.bolts are used to compress each rubber layer to approximately l/a-in. thickness between the plywood sections; each bolt is fitted with a metal washer and a rubber washer and is countersunk into the wood. By placing the bolts about 12 inches apart in each direction it is possible to draw down the plywood layers until a uniform thickness of sponge rubber is obtained. The bottom and middle layers of wood are bolted together, as are the middle and upper sections, but there is no direct connection between the upper and bottom wooden sections. This mount has been entirely satisfactory in protect,ing a sensitive microelectrophoresis apparatus from the disturbances caused by numerous nearby air compressors and two heavy overhead fans. Its per-
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Journal of Chemicol Education
formance has been considerably more efficient than a commercially-available metal base ordinarily recommended for such uses. YIBRI\TION-FREE MOUNT
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UPPER AND MIDDLE LAYERS BOLTED
* L A Y E R S BOLTED
Diagram of vibration-free mount (not drawn to scale).
RUBBER STOPPERS
