Keuffel & Esser Slide Rule Display

This display of steps in the manufacture of slide rules also demonstrates the capability of dividing engines. It may have been assembled by Keuffel & Esser executives when the company donated two of its early 20th-century linear dividing engines (335265 and 335266) to the Smithsonian in March 1971. The exhibit consists of a large dark green pegboard, to which slide rule components are fastened with wires and labels are attached with tacks.

The left panel displays the raw materials of slide rule manufacture: a rough mahogany slab, a planed mahogany slab, white xylonite (celluloid) to face the front and back of the wood, and a toothplaned mahogany slab. Each slab is approximately two feet long.

The middle panel shows the xylonite glued to a toothplaned mahogany slab, which is then depicted as cut in half to make two ten-inch slide rule forms. The forms are cut lengthwise in thirds, and then the edges are grooved so that the middle part slides between the two parts of the base. Next, a blank slide rule is machine divided.

The right panel displays slide rules that have been numbered and blackened, numbered and reddened, and ready to be assembled with L-shaped metal end pieces and screws. The assembled slide rule has been removed. Another example with front and back views of a completed model 4081-3, Log Log Duplex Decitrig, slide rule is missing the slide in the back view. Finally, the parts of an indicator are mounted on a card: two pieces of glass, two pieces of metal frame, one of the two plastic edges, and four screws. Compare the completed example to 318482, 334387, and 1990.0687.01.

References: Accession file; Michael P. O'Leary, "The Keuffel & Esser Logarithmic Dividing Engine," Journal of the Oughtred Society 11, no. 2 (2002): 35–40; Bob Otnes, "An Interview with Jack Burton and Gordon Anthony: The End of the Slide Rule Era at Keuffel & Esser," Journal of the Oughtred Society 7, no. 2 (1998): 18–24, 8, no. 1 (1999): 18–23, and 8, no. 2 (1999): 27–31.

Currently not on view