Clip-On Extensometer Purchasing & Configuration Guide

christopherthomasb
Aug 7
3 min read

Clip-On Extensometers for any Universal Testing Machine

If you're evaluating a clip-on extensometer for your tensile testing machine, this guide is for you. Whether you're testing plastics to ASTM D638, metals to ASTM E8, or composites under ASTM D3039, choosing the right extensometer ensures accurate, repeatable results while protecting your investment.

At Universal Grip Company, we offer Epsilon clip-on extensometers—recognized for their durability, precision, and compatibility across most universal testing machines (UTMs). Each unit is custom-configured to match your machine and testing requirements.

What Is a Clip-On Extensometer?

A clip-on extensometer is a mechanical strain measurement device that attaches directly to the specimen during a tensile or compression test. These devices provide real-time, high-precision strain readings in compliance with standards such as ASTM E83, and are widely used across industries such as plastics, metals, composites, and elastomers.

Unlike video extensometers, which measure displacement optically from a distance, clip-on extensometers offer high accuracy at a lower cost, typically around $4,000–$5,000 per unit.

Clip-On Extensometer for Strain Measurement on a Universal Testing Machine — Clip-On Extensometer for ASTM E8

What to Know Before Purchasing

To help you select the correct clip-on extensometer for your application, we need to understand your material, geometry, and testing machine. Here's the essential information we typically request from customers:

1. Type of Material & Sample Geometry

Tell us the type of sample you're testing and the applicable standard. Examples include:

This information helps us determine the jaw opening and required arm geometry of the extensometer.

2. Starting Gauge Length

Typical options include:

25 mm
50 mm
1 inch
100 mm

The gauge length must match the requirement of your test standard and be supported by your grips or specimen design.

3. Maximum Strain Measurement

How much strain will your material experience before failure? Common values include:

10% (for metals)
50% (for semi-rigid plastics)
100% or more (for elastomers)

This impacts the extensometer’s range and internal spring mechanism.

4. Testing Machine Compatibility

To ensure plug-and-play functionality, we need:

A photo of the rear of your UTM showing the extensometer input
The model number of your machine (usually found on the backplate)

We’ll configure the electrical interface, connector type, and calibration settings to match your specific machine—whether you’re using Instron, MTS, Zwick/Roell, Tinius Olsen, or another brand of Universal Testing Machine such as Galdabini from Italy.

Example Clip-On Extensometer Configuration

Here’s a sample configuration that one of our customers recently purchased:

Application: ASTM D638 tensile testing of polypropylene plastic Sample Geometry: Type I, 165 mm x 13 mm x 3 mm Gauge Length: 50 mm Max Strain: 100% Testing Machine: Instron 3367 Extensometer Connector: 3-pin round DIN, 5V excitation

We configured an Epsilon 3542 extensometer with:

50 mm gauge length
±50% strain capacity (suitable for up to 100% total elongation)
Electrical connector matched to the Instron input
Pre-calibrated for plug-and-play installation

The customer was able to run ASTM D638 tests with high accuracy and repeatability immediately upon delivery.

When to Consider a Video Extensometer

If your application requires:

Multiple extensometers for different gauge lengths
Testing soft or thin specimens where clip-on weight affects performance
High-throughput environments with frequent operator handling

... then a video extensometer may be the better long-term investment.

Our video extensometer systems start at a price of around $20,000 and provide non-contact strain measurement, removing the possibility of human error or sample slippage due to clip-on weight.

Why Buy From Universal Grip?

✅ Expert Configuration – We ensure your extensometer works seamlessly with your specific UTM.
✅ Turnkey Setup – Each unit arrives calibrated and ready to use.
✅ Top Brands – We are an authorized distributor of Epsilon extensometers, made in the USA and compliant with ASTM and ISO standards.
✅ Support You Can Trust – We offer full installation support, training, and ongoing tech support.