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Bridgeport Machines, Inc., is amachine tool builder founded in 1938 in theUnited States of America.[1] It manufacturesMilling machines andLathes.
Bridgeport mills are still widely used in metalworking applications, including milling slots, gears, and fixtures in steel and aluminum, and remain common in CNC-equipped automotive machine shops in South Korea.[2]
The original corporation was founded inBridgeport, Connecticut, and started selling its machines in 1938. It became known in the following decades for small and medium-sized vertical milling machines, with a form ofquill equipped multiple-speed vertical milling head with a ram-on-turret mounting over a knee-and-column base. TheAmerican Precision Museum's biography of Rudolph Bannow[3] reports that he conceived the design in 1936 as the logical machine on which to mount the milling head already being built by the Bridgeport Pattern and Model Works (which he owned with a partnerMagnus Wahlstrom). The first Bridgeport milling machine (serial number 1) is on display at the Museum.[4]
Due to the overall success of the company's milling machines, the term "Bridgeport" is often used to refer toany vertical milling machine of the same configuration, regardless of make. Many other companies have cloned the form. Today, the Bridgeport brand still produces this configuration in both manual andcomputer numerical control (CNC) versions, and such machining centers are now equally as prominent as their manual counterparts.
Bridgeport manual milling machines came in many types and sizes over the years, including (but not limited to) the C head (original), R head (heavy duty C head), M head, J head (and high speed, 5440 RPM version), 2J1 1/2 head (1.5 HP Vari-Speed), 2J2 (2HP Vari-speed), and Series II head (4HP Vari-speed). All of the heads offered variable speeds, the earlier ones via astep pulley (cone pulley) and the later ones via eithercontinuously variable transmission (CVT) systems orvariable-speed drive. Typical table sizes were 9″ × 49″ (Y and X, respectively) and 10″ × 54″.Machine tapers for tool holding includedMorse tapers (on early models) and theR8 taper (a widely used standard that Bridgeport created) on most models. Both Morse and R8 allowed for bothcollets and solid holders, and adrill chuck could be held by either of the latter. Currently R8 and Erickson #30 Quick Change tool holders are available. Machine slides are of the dovetail type, and rotary bearings are mostly of theroller andball types.
Through 1970, Bridgeport turret milling machines were made under licence by Adcock-Shipley, a UK manufacturer of horizontal and vertical milling machines founded during WW1. Bridgeport machines were built in two UK plants, Bridlington in Yorkshire and Forest Road in Leicester for the UK and international markets. By 1975 Bridgeport had acquired Adcock-Shipley and by 1980 had opened an assembly plant in Singapore to serve the Australasian market.
