My husband did some research on this vintage light, both in my dad's vintage electronics catalogs "collection" and on line, and here's a bit of what he found:
DESCRIPTION: This RARE museum-quality artifact is a new old stock vintage jewel pilot light assembly, manufactured by the Drake Manufacturing Co., of Chicago, USA. This instrument panel indicator is an open socket design, which consists of three components: the socket assembly, the jewel assembly, and a mounting plate. The pilot light assembly has an S-6 type Sylvania 130-volt, 6-watt incandescent lamp, which was tested in the unit with 110 VAC and photographed during the test (see photos). The thermoset socket accommodates a candelabra base lamp, and appears to be molded, high-impact, phenolic, rated for 75 watts at 125-volt service. The jewel assembly is designed to fit a panel accommodation hole with a diameter of 11/16 inch, and can be mounted in panels with thickness up to 1/4 inch. The bulb is replaceable from behind the panel by depressing the spring-steel side brackets to detach them from the mounting plate -- a unique attribute of this ingenious design!! The spectacular 11/16" faceted green jewel is mounted in what appears to be a chrome-plated bezel. Discriminating buyers covet these vintage artifacts for their quality construction. They are especially desired for the restoration of vintage equipment, where OEM component are preferred.
MANUFACTURER: Drake Manufacturing Co., Chicago, Illinois, USA
COMPANY HISTORY: The Drake Manufacturing Co. of Chicago, Illinois, was established in 1932, born in the depths of the Great Depression. In January, 1938, the firm filed its patent application and received #2220515 for its original No. 20 type pilot light assembly, assigned to Drake by the inventor, Albert J. Foute. An application for a second patent (#2220516) was filed by the company for its No. 50 type pilot light assembly in April, 1938. The applications stated that Drake was a partnership consisting of Albert J. Foute and Irman (or Irmin) D. Foute, perhaps Albert's wife, Irma D. (See official Gazette of the US Patent Office, Vol. 520 (Nov. 1940), pgs. 152-3. A September, 1939, advertisement in Communications magazine stated that Drake offered "hundreds" of pilot light types, including "Underwriters approved" designs. A product catalog was available. In June, 1939, Albert J. Foute was recorded as the proprietor of Drake Manufacturing, which was then advertising its Dial or Jewel Pilot Light Assemblies in Radio Today magazine. By 1939, Drake Manufacturing Co. claimed that "within a few years" it had become "the world's largest, exclusive manufacturers of Dial and Jewel Light Assemblies." By that time (1939), they were offering design engineering services for custom builds and claiming that their business had attracted the attention of a majority of America's radio manufacturers. The Drake factory, at 1713 W. Hubbard St., was located in Chicago's West Town neighborhood. During WWII, the company supplied dial and jewel pilot light assemblies, miniature lighting and lights for military projects to the U.S. armed forces under manufacturer code "CAYS." Their military trade catalog (SILNMAHTL_13452) is archived at the Smithsonian National Museum of American History. In the early 1960's, Drake Manufacturing Co. moved to 4626 N. Olcott Ave. in Chicago's Harwood Heights Community, where it employed 140 people by 1967. By 1975, Drake had been acquired by the General Instrument Co.
MAXIMUM PANEL THICKNESS: 1/4-inch
POWER RATING: Sockets are rated for 75 watts at 125 volts (molded in base)
TERMINALS: Two, rear-mounted, 1/4-inch wide, tab terminals
LAMP: 130-volt, 6-watt, incandescent lamp (included). The lamp has a candelabra screw base and an S6-style bulb.
JEWEL: Spectacular, 11/16-inch, faceted, green jewel, mounted in a bezel
TRANSMITTED LIGHT: Translucent, or transparent light transmitted for limited, axial viewing
BEZEL: Lens holder appears to be chrome plated, and has a male thread that screws onto the unit's mounting plate.
DIAMETER OF PANEL ACCOMMODATION HOLE: 11/16-inch
BODY: Open design, with two spring-steel brackets, spin-riveted to the socket
MAXIMUM WIDTH: About 1.2-inches (over mounting plate)
OVERALL LENGTH BEHIND PANEL: About 2-19/64-inches (over mounting plate and terminals)
WHO WANTS IT?? Public or private museums, collectors of Drake products and other vintage electronics, Hot Rodders and Rat Rods, and restorers of vintage equipment
(pilot light box, radio shelves)