magnetic drums

This section of the SAGE "Theory of Operation of Drum System for AN/FSQ-7 Combat Direction Central and AN/FSQ-8 Combat Control Central" document (1958) talks about the composition of the magnetic drum rotors: "Section 2.3.3.2 Drum Rotor The magnetic drum rotor (figs. 1-5 and 1-6) is a Monel metal cylinder, coated with copper and plated with nickel-cobalt. The 0.01-inch copper coating fills the porosity of the Monel metal and provides a diamond polished surface. The 0.0005-inch nickel cobalt plating is a dia-magnetic alloy characterized by high remanence. This plating provides the magnetic storage capabilities of the drum surface. The rotor is 10.7 inches in diameter, 12.5 inches long, and weighs 105 pounds. Its shaft is mounted on ball bearings and has a toothed pulley connected by a belt to the drum motor pulley." Mike Loewen mloewen at cpumagic.scol.pa.us Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/