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Strain measurement for materials testing is Epsilon’s sole business


Over forty years of experience have gone into the development of Epsilon’s products. At their facility in Jackson, Wyoming, they design and build extensometers for testing around the world.


Extensometers are available for testing almost all engineering materials, including metals, composites, plastics, ceramics, elastomers, geomaterials (e.g. rock, concrete, and asphalt), and biomaterials including bone.


There are models for tiny and delicate samples, including relatively fine wire, up to massive metal samples and large rock cores. The huge variety of models covers nearly every type of test as well, including: tensile, compression, bend, fracture mechanics, and cyclic strain controlled tests like low cycle fatigue. Many of our extensometers are capable of relatively high frequency operation as well.


Some key aspects of Epsilon:

  • World’s largest extensometer manufacturer
  • Unrivaled quality
  • Responsive – talk to our experts anytime
  • Broadest product line anywhere
  • Expertise – in both testing and extensometers

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Epsilon's Technology Product Line




  • Optical and laser extensometer models for non-contacting axial tension and compression
  • Optical models may also be used in strain control and for cyclic testing at >100 Hz
  • One system for many different tests, measuring ranges, and gauge lengths

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  • 7 models in this group cover tension, compression and cyclic testing
  • Huge variety of gauge lengths and measuring ranges
  • Temperatures from -270 to +200 °C

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Hoge Temperatuur Axiaal

High Temperature Axial


  • 5 models cover a variety of applications for high temperature testing
  • 1 un-cooled model for use inside chambers up to 700 °C (1300 °F)
  • 4 models for use with split furnaces and induction heating up to 1600 °C

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Breukmechanica Clip-on

Fracture Mechanics clip-on


  • 3 models cover a broad range of gauge lengths, measuring ranges and temperatures
  • For fracture mechanics and fatigue crack growth tests in compliance with various standards
  • Temperatures from -270 to +1600 °C

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  • Widely used for 3 and 4 point bending tests, compression tests and general deflection measurement

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Transversaal & Diametraal

Transverse & Diametral


  • 4 models cover most any test requirement and can be used with axial extensometers at the same time
  • Miniature and standard units
  • Extensometers for r-value of sheet metal
  • Available options cover temperatures from -270 to +200 °C

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Trans & Dia - Hoge Temp

High Temp Trans & Dia


  • 1 un-cooled unit for use inside chambers to 700 °C (1300 °F)
  • 1 model for use with split furnaces and induction heating, to 1000 °C

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Extensometer voor Steen beton asfalt

Rock, Concrete & Asphalt


  • 7 models cover axial, circumferential and diametral testing on aggregate material

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Gemiddeld, Bi-axiaal & Torsie

Average, Bi-axial & Torsion


  • 4 models for axial averaging, axial/transverse, axial/torsional, and in-plane biaxial over a wide range of temperatures
  • Temperatures from -270 to +1600 °C

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Bouten & Afschuiving

Bolt Proof & Lap Shear


Specialized extensometers for

  • Bolt proof testing and elongation measurement
  • Elongation of rebar splice assemblies
  • Lap shear, sandwich core shear, and rigid cellular plastic shear
  • Testing while submerged in liquids

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Extensometers op maat



  • Examples of modified standard extensometers and application-specific extensometers

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Knife Edges


  • A complete selection of knife edge styles to match many different specimen types and applications

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Interface Electronica

Interface Electronics


  • For customers who do not have signal conditioning as part of their test controls
  • 1 analog and 4 digital versions for strain gaged sensors

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  • 2 digital models. Choice of 1 micron or 20 nanometer resolution (50 microinch or 0.8 microinch), both with 50 mm (2 inch) travel.
  • 1 model for axial/torsional calibrations
  • Provided with calibration traceable to NPL

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Kalibratie Referenties

Calibration References


  • A simple and inexpensive way to transfer Epsilon’s calibration of an extensometer to the signal conditioner in your test system controls

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Frequently asked questions about extensometers

An extensometer is a precision measuring instrument used in materials testing to accurately measure changes in length or strain of a material specimen under mechanical loading. It provides essential data for evaluating the mechanical properties and deformation behavior of materials.

Extensometers are typically attached to the surface of a test specimen, and as the specimen is subjected to mechanical stress, the extensometer measures the resulting changes in length or strain. These measurements are then recorded and analyzed to determine the material’s mechanical characteristics.

There are various types of extensometers, including clip-on extensometers, contact extensometers, non-contact extensometers, and strain gauge extensometers. Each type has its specific applications and advantages.

Clip-on extensometers are attached directly to the sides of a test specimen. They typically use contact arms or clips to measure the change in distance between two reference points on the specimen as it is deformed.

Contact extensometers make direct physical contact with the surface of the specimen during the test. They use mechanical arms or pins to measure the elongation or compression of the material.

Non-contact extensometers use optical or laser technology to measure the deformation of the specimen without physically touching it. They are ideal for testing delicate or sensitive materials.

Strain gauge extensometers use strain gauges attached to the surface of the specimen to measure changes in strain. These extensometers are highly accurate and can be used for various materials and test conditions.

Extensometers provide precise and reliable measurements of strain or deformation, allowing researchers and engineers to understand a material’s mechanical properties, such as Young’s modulus, yield strength, and elongation.

Extensometers offer several advantages, including increased accuracy and repeatability of test results, improved data quality for material characterization, and better control over the testing process.

Selecting the appropriate extensometer depends on factors like the material type, test conditions (temperature, loading rate), required accuracy, and budget constraints. Consulting with experts and understanding the specific testing requirements is essential for making the right choice.