Southwestern Industries, Inc. manufactured the Trav-A-Dial measurement system that was a predecessor to digital readouts (DROs).

Merville E. Hodge invented the Trav-A-Dial. In 1958 M. E. Hodge Corp., Pasadena, CA, began manufacturing the Trav-A-Dial. It appears that these early versions were trouble-prone and M. E. Hodge ceased manufacturing them after about a year. In 1962 the rights to Trav-A-Dial were acquired by Southwestern Industries Inc., which quickly introduced an improved version to the market.

Southwestern Industries was owned by former Lockheed engineer Frederick Jenks. Improvements to the Trav-A-Dial were developed by another Lockheed alumnus, Irven Culver.

The Trav-A-Dial was very successful during the 1960s and '70s. Gradually, however, sales began to sag due to the development of digital readout systems (DROs) and CNC machining, as well as a gradual decline in the US machine tool industry. The Trav-A-Dial remained in production into the 2000s. Some parts are still available through Southwestern Industries.

Information Sources

• The label on the back of a Trav-A-Dial reads, "Southwestern Industries, Inc. / 5880 Centinela Ave. / Los Angeles Calif. 90045"
• From a page on the southwesternindustries.com website.

  Founded in 1951 by former Lockheed engineer Dr. Fred Jenks, SWI was originally located in a facility on the border between the present-day cities of Culver City and Inglewood, CA. Established as a job shop, the company's primary focus was the development and manufacture of mechanically actuated electrical pressure switches to control fuel flow for Atlas and Delta missiles as well as actuators for the U-2 and SR-71 spy planes.

  The Trav-A-Dial
  Dr. Jenks bought the design rights to the Trav-A-Dial in 1962. Although the idea behind the design was right, the original version of the product did not meet expectations. In order to address this issue, Dr. Jenks assigned Trav-A-Dial re-design responsibilities to Irv Culver, the legendary Lockheed Skunkworks engineer who had recently left Lockheed to join SWI. Irv’s redesign resulted in what could arguably be called the most universally used machine tool measurement device of the 1960’s, 1970’s, and 1980’s.

• 1958 issue of Western Machinery and Machinery World (page 84).

  Measuring Indicator—The 'Trav-A-Dial,' by M. E. Hodge Corp., is a measuring indicator, applicable to practically any machine tool, that measures complete longitudinal travel of machines and—on certain tools—transverse and vertical travel as well. The instrument reads any length in 6 inches increments and so furnishes a visual record in inches, hundredths and thousandths all easily read on a large dial.

• 1958 issue of Machinery (volume 93 page 1080).

  Trav-A-Dial, introduced by the M.E. Hodge Corporation, Pasadena, California, U.S.A., for accurately measuring the movements of slides on machines was shown by the sole agents in this country, A. P. Warren, Ltd., Carl Edvard House, Sheen Road, Richmond, Surrey. The instrument is secured to a slide, and a neoprene "O" ring, fitted to a built-in friction drive wheel, is held in contact with a machined surface on a fixed part of the machine by spring pressure. When the slide is traversed on its guideways, two pointers on the dial indicator are rotated by the action of the friction wheel. The scale associated with the fairly long, centrally-mounted, pointer gives readings to 0.001 in., and the second scale indicates movements of the slide up to 1 in., and is divided into tenths. There is a separate circular scale which gives readings in inches for slide travels up to 6 in. This scale—and with it the friction wheel and both pointers on the dial indicator can be rotated freely by a knob for zero setting. In addition, the scale for the first pointer can be turned by hand so that the instrument can be set accurately for zero. The body which carries the dial indicator can be moved on dovetail guide-ways in the base by means of a small lever. In this way, the friction drive wheel can be brought clear of the contact face on the machine, to disengage the instrument.

• 1959-01-27 US Trademark registration: S/N 56,130. M. E. Hodge Corporation, Pasadena, Calif. Filed July 28, 1958. / TRAV-A-DIAL / "For Measuring Devices of the Type Which Measure Relative Travel Between Members, Such as Members of a Machine Tool or the like. First use Feb. 20, 1958." Southwestern Industries, Inc., held the following trademarks on Trav-A-Dial: S/N 72056130 (registration no. 0676962), and S/N 72121768 (registration no. 0741257. Other Southwestern Industries trademark registrations were for TEDD (72276182 / 0852287), ORIENTER (72340436 / 0896872), TRAK (73000863/1040028, 75062653/2267982), 75168305/2087772, 87067670/5124083), QUIK CELL (75450493 / 2312473), PROTO TRAK (76643938 / 3128534).
• 1961 issue of Canadian Metalworking (volume 24 page 51).

  A useful instrument for production shops and tool rooms, called the Trav-A-Dial indicator, is being manufactured by Southwestern Industries, Inc. It provides a provides continuous indication of carriage, slide or tool position in relation to work piece within .001" and attaches to any machine tool with a special spring-loaded mount and a fabricated bracket. Measurements are made by a gauge wheel contacting a way or machined surface. Motion is transmitted through two precision gear trains to a dial indicator reading in thousandths which is equipped with a bezel for instant zero adjustment. A dial knob, graduated in inches and 1/10", gives a continuous motion record up to 6" of travel, repeating thereafter on any length of traverse. The dial contains a built-in slip clutch which now permits full zeroing adjustments without disengaging the gauge wheel from its contact surface.