The Dakota NDT BT1-DL is an ultrasonic bolt tension monitor designed to accurately measure the elongation of threaded fasteners under load. By using pulse-echo ultrasound, it is not affected by temperature, friction, or resistance factors that limit the accuracy of standard torque measurement techniques.

The instrument measures multiple quantities including time (nanoseconds), elongation, load (KIP or MPa), stress, and %strain. Resolution is 0.0001mm (0.00001in) with zero crossing detection. Measurement range extends from 25.4mm to 15.24m (1in to 50ft), covering virtually any fastener material and size.

A 4GB internal memory stores over 8,000 readings with associated waveforms, organized in sequential or grid formats. Up to 64 custom user-defined setups can be saved for different bolt types and applications. The Auto Set feature automatically optimizes gain, detection, and display settings for each bolt.

Temperature compensation is automatic using an external probe, ensuring accuracy across varying conditions. Field calibration options include vector or regression correction for increased precision using load and stress references. Adjustable hi/lo alarm limits with visual LEDs and audible alerts provide immediate pass/fail indication.

The display offers A-Scan in rectified or RF modes, plus a large digits view with alarm limits bar. Screen refresh rate is 30Hz. USB-C connectivity enables direct data transfer to PC for analysis and reporting.

Constructed with an extruded aluminum body and sealed end caps, the BT1-DL meets IP65 requirements for harsh environments. Operating temperature range is -10°C to 60°C. Power is supplied by three AA batteries with up to 35 hours of operation.

Applications include wind turbine bolt inspection, automotive frame assembly, bridge structure maintenance, and theme park ride safety checks.

Features

• Measures time, elongation, load, stress, and %strain ultrasonically
• Resolution: 0.0001mm (0.00001in)
• Measurement range: 25.4mm to 15.24m (1in to 50ft)
• 4GB internal memory for 8,000+ readings with waveforms
• 64 custom user-defined setups
• Auto Set automates detection and display optimization
• Automatic temperature compensation
• Vector or regression field calibration
• Adjustable hi/lo alarm limits with LED and audible alerts
• A-Scan (rectified/RF) and large digits display
• USB-C connectivity for PC data transfer
• IP65 rated enclosure
• Supports 1-10MHz single element transducers
• Includes NIST-traceable calibration certificate