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At Gurley Precision Instruments, measurement is our business. GPI was one of the first companies to develop the chrome-on-glass process necessary to manufacture optical encoder discs, and has since been a significant provider of optical encoders, optographic products and related devices. This tradition and commitment to measuring excellence is still very much alive today - as we offer as many standard and custom encoder options as any company in the business. Incremental, absolute and Gurley's own Virtual Absolute technologies in enclosed and modular rotary and linear configurations - each is available in prototype and OEM quantities.

Industries that have benefited from Gurley Encoders include:

Precision In Air, On Land and Sea - general aviation and defense industries

Precision on the Factory Floor - position, speed and direction in a wide variety of industrial processes from the slow and simple to the high speed and complex

Bringing the Electronic Image to Hand - high performance for the printing and graphic arts industries

A Common Denominator in Instrumentation - measuring instrumentation includes products such as dynamometers, gear checkers, torque testers, coordinate measuring machines (CMMs) and cam profilers

Increasing Machine Tool and Robotics Productivity - Gurley encoders are designed to handle harsh environments while delivering undiminished performance

Tracking and Positioning in the Sky - radio and optical telescopes, radar pedestals, tracking mounts and communication antennas

At The Heart of Medical Diagnostics - Gurley's high-reliability encoders are essential in scanning instruments for MRI, x-ray and nuclear imaging systems, as well as fluid analysis devices

Gurley is an ISO 9001 certified company.


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Since 1845, Gurley has been a major designer and producer of measuring instrumentation for a variety of industries and applications. Our areas of expertise include optical encoders for the precise measurement of position or speed; digital readout systems for retrofitting machine tools; generation and replication of precise patterns on glass and similar substrates; physical properties test instruments for medical tubing, paper, films, textiles, and other sheet goods; mechanical components; and open-channel flow meters to measure water velocity. 

       We received ISO-9001 certification in January, 1996.


      We offer Optical Encoders for both rotary and linear motion, in conventional incremental and absolute configurations and in GPIs unique Virtual Absolute technology. They are used to measure or control position and/or speed in medical instrumentation, electronic manufacturing equipment, robotics, factory automation, graphic arts and printing equipment, machine tools, radar pedestals, and high speed scanners.

Our self-contained rotary incremental encoders are available in a variety of sizes, from 0.75" dia with up to 40,960 counts/rev, to a 6" dia model with 3,600,000 counts/rev. An industrial-grade rotary absolute encoder offer resolution up to 217 words/rev. Modular rotary incremental encoders provide a wide choice of size and resolution, while linear encoders come in many mounting configurations, lengths, and accuracy grades. Virtual Absolute encoders are available as rotary or linear encoders in both self-contained (housed) and modular configurations.

Gurley specializes in providing customized solutions to specific problems, whether the answer is a low-cost encoder for high production volumes or a very high performance encoder for military or aerospace applications.

       Digital Readout Systems (DRO's) are an add on accessory for machine tools to provide the machinist with information regarding the position of the cutting tool on the work piece. A system consists of linear encoders which are attached to the machine tool and a digital display unit which is connected to the linear encoders. Systems are easily added to milling machines, lathes, horizontal and vertical boring mills, grinders, jig borers, or any other type of machine tool.

      We offer glass-scale encoders for lengths up to 7 ft, and rack-and-pinion encoders for virtually any length on large machines. We provide resolutions as fine as 1m (50in). The PointFinder DRO offers all the popular features of CRT-based systems with the visibility, reliability, and price of a standard LED display.

      Our Optics and Optographics product line comprises the generation and replication of precision optical patterns and parts such as reticles, resolution targets, encoder discs and scales, prisms, mirrors, beam splitters, filters, lenses and step wedges. The patterns are most commonly vacuum deposited chrome on glass; however, we also work with other pattern materials such as silver, inconel, aluminum, and photographic emulsion. Other substrates include plastic, fused silica (quartz), sapphire, mylar film, zinc selenide, silicon, germanium, and zinc sulfide.

      We have some catalog items, but over 90% of our sales are items fabricated to meet customer's drawings and specifications. The products are used in fire-control systems, optical encoders, guidance systems, and other types of optical, electro-optical, and laser based systems operating in either the visible, infrared, or ultraviolet portion of the spectrum.

       Hydrological Instruments are used to measure flow velocity in open channels such as rivers, streams, tidal marshes, sewers, flumes, conduits, etc. The product line comprises two models of bucket-wheel flow meters that cover the velocity range of 0.015 to 7 m/s. There are two readouts available: an earphone assembly that is used to count clicks over a fixed period of time, and a completely automatic hand held digital display.

      Genuine GurleyTM Film, Sheet, and Paper Testing Instruments have been the industry standards for decades for measuring physical characteristics such as stiffness, flexibility, softness, porosity, air-permeability, and smoothness. Gurley instruments are used extensively in the paper manufacturing, paper board converting, printing, medical product manufacturing, and textile/non-woven industries. While used most often to test thin flat materials, small dimensional parts such a tubing can also be tested.

      To meet the needs of measuring those characteristics over a wide range of parameters, we offer three models of stiffness testers, seven densometers, and a permeometer.

       New for 2001 - Mechanical Components and Assemblies!  Gurley now offers precision mechanical parts and assemblies.  Please visit the web site for more information and register for the chance to win a Palm Handlheld. 

Gurley Historical Sketch


Written by Bill Skerritt 

      The Gurley enterprise was established in 1845, first as the partnership of Phelps & Gurley and in 1852 as W. & L. E. Gurley.  William Gurley and his younger brother Lewis E. were both engineering alumni of Rensselaer Polytechnic Institute, in Troy, NY, and brought to the business a hunger for technical innovation and unrivaled marketing skill.  Exposure at the Centennial Exposition in 1876 launched the company into international prominence from which it never fell.  The brothers built a factory in 1852 that operated in departments, each department turning out different components, which were then assembled.  This revolutionized the industry which, to that time, operated as small shops making, essentially, individual instruments.  Gurley was able to roughly halve the price of their instruments over those of their competition, while maintaining quality.

      Throughout the 19th century Gurley continued to expand its product line and gradually moved into others.  In 1885 Gurley began making hydrologic equipment, like current meters; in 1903 they opened a department of Weights & Measures; in 1905 they acquired Charles Wilder Thermometers and moved it to Troy; in 1908 they opened Department P, making mechanical, electrical, and scientific apparatus; in 1923 they launched a line of paper testing equipment; and in the 1950s moved into applications of optical encoder technology.

      Incorporated in 1900, Gurley responded to the worldwide demand for their products by opening the Seattle Factory Branch in 1909, to serve the Pacific Rim and Asia.  Gurley remained highly visible to the engineering and surveying professions by supplying instruments to major engineering projects and to expeditions, like Admiral Byrd's.  During World War II, Gurley distinguished itself by winning coveted Army-Navy E Awards for outstanding contribution to the war effort.

      Teledyne Corporation purchased W. & L. E. Gurley in 1968 and the company became Teledyne Gurley.  Production of surveying instruments ceased in 1980 in the face of stiff foreign competition and the technological shift away from optical instruments.  In 1993 Teledyne sold Gurley and the company became Gurley Precision Instruments, Inc.

Copyright 1996-2006 Gurley Precision Instruments, Inc. All Rights Reserved