How It Works - SmartBolts

TORQUE VS. TENSION

For many professionals in industries such as mining, construction, aerospace, and manufacturing, torque is often the standard measure for tightening bolts.

However, torque alone doesn’t reflect the actual tension within the bolt — the true force that holds a joint securely together.

Without understanding this difference, there’s a risk of improper tension, leading to potential equipment failures and higher maintenance costs.

Tension or stretching force is the only factor that ensures your joint is “tight”.

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Torque

Rotational force
measures how hard it is
to turn a bolt (or nut)

TENSION

Stretching force is a
certain amount of bolt
tension that makes your
joint secure

CLAMP FORCE IS MEASURED

SmartBolts measure tension by converting the elongation of a fastener as it is tightened into a repeatable and accurate color change. Fasteners stretch when tightened, like a spring or rubber band, and this creates tension within the bolt. Measuring tension is the best way to keep a bolted joint secure because tension creates clamp force. Clamp force holds a bolted joint together and keeps it from loosening

AN INTERNAL PIN MOVES AS THE BOLT STRETCHES

SmartBolts are ordinary bolts retrofitted with a gage pin affixed in the bolt shank. As the bolt stretches, the gage pin moves with the stretch, and this minute movement causes our visual indicator to predictably change color. This provides the user with an accurate measure of bolt tension.

A SIMPLE VISUAL INDICATION OF TENSILE LOAD IS SHOWN

The embedded visual indicator in every SmartBolt is a color-calibrated real-time display of tensile load. The indicator is bright red when the fastener is loose and gradually changes to black when the fastener is tightened to its desired tensile load.

When the load is released, the indicator changes back to the bright red color. A fastener with our visual indicator provides constant verification that critical bolted joints are safe and secure, without any extra tools, batteries, or monitoring devices.

SMARTBOLTS WHITEPAPER

“Measure What Matters – The Hidden Secrets of Successful Bolting,” reveals why traditional torque measurements aren’t enough. It’s time to focus on what truly matters—tension.

Whether in mining, manufacturing, infrastructure, or beyond, this guide offers actionable insights to elevate your maintenance practices.

Unlock the secrets of successful bolting.

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