Product Description
Technical Specification
Instruction Manual

BG80 Bolt Tension Monitors

When nuts and bolts are fastened together under load the action of tightening the nut increases the force applied to the bolt causing elongation.

The BG80 Series of bolt tension monitors accurately measure this elongation allowing the gauges to accurately measure time (nanoseconds), elongation, load, stress, and %strain of the bolt.

By using ultrasonics, bolt tension monitors are not affected by temperature, friction or resistance factors affecting the accuracy of standard torque measurement techniques - giving the BG80 Series accuracy within 0.0001mm (0.00001 inch).

Using the gauge's RS232 interface together with the optional shut off accessory the gauge can be programmed to automatically stop the tightening process when the appropriate load has been applied.


  • Range of display & measurement options including
  • Elongation, Load, Stress, and %Strain, RF, Rectified, Large Digits with Limits Bar
  • BG80TDL features temperature compensation to counteract measurement irregularity caused by temperature change
  • Data storage capability: 8,000 readings and waveforms
  • Auto Set feature automatically optimizes detection and adjusts display
  • Hi/Lo Alarm tolerance limits work in conjunction with the data port


How does it work?


bolt tension 

As a fastener is tightened it stretches (elongates) in length.

Manual torque wrenches measure the force applied when tightening a fastener, the accuracy can be affected by temperature, friction and resistance.

As BG80 & BG80TDL ultrasonically measures the change in length accurately determining the applied load of a fastener as it is tightened, they are not affected by these factors.


Technical Specification

Model & Part Number BG80DL & BG80TDL
Material thickness digits display

Measurement Mode1 PE & PE with Gate
Measurement Rate:

4 readings per second
Measuring Range2 25.4 - 1370mm (1 - 48 inches)
Measurement Accuracy2

± 1% or ±0.1mm whichever is the greater

Measurement Resolution 0.0001mm (0.00001 inch)
Velocity Calibration Range 1250 - 10,000m/s
0.0492 - 0.3937in/μs
Additional Features:  
Limit alarm mode

Data logging 8,000 readings
Calibration Options fixed, single & 2 point
Transducer Probe Type single element
Transducer Frequency Range 1 - 10MHz
Display 1/8 VGA
Units (selectable) mm or inches
LED Backlight on / off / auto
Repeatability / Stability Indicator

Battery Type 3 x AA alkaline
Battery Life (approximate) 150 hours
Low Battery Indicator

Battery Save Mode auto
Operating Temperature -10 to 60ºC (14 to 140ºF)
Size (w x h x d) 63.5 x 165 x 31.5mm
2.5 x 6.5 x 1.24 inches
Weight (including batteries) 383g (13.5oz)
Aluminium case design with gasket sealed end
caps, waterproof membrane keypad

Transducer Connector Type LEMO
RS232 Interface

Packing List

Elcometer NDT BG80DL or BG80TDL gauge, couplant, carry case,

user manual, test certificate, 3 x AA batteries, ElcoMaster™ software,

RS232/DB9 & USB/DB9 transfer cable


¹ PE: Pulse-Echo Mode

² Measuring range & accuracy depends on material, surface conditions and the transducer selected


Cables & Adaptators  
TL-24030-3 T/Cable: 4' Single Lemo 00 to Microdot
TL-24030-10 T/Cable: 10' Single Lemo to Microdot
TL-24030-11 T/Cable: 20' Single Lemo to M/dot Single
TL-24030-12 T/Cable: 20' Lemo to Lemo 00
TL-24031 RS232 Cable (6'); DB-9 to Lemo
TL-24032 USB to Serial Adapter
TC-24034-1 Couplant: Standard; 4oz Bottle (Material Safety Data Sheet)
TC-24034-2 Couplant: Standard; 12oz Bottle (Material Safety Data Sheet)
TC-24034-3 Couplant: Standard; 1 Gallon (Material Safety Data Sheet)
TC-24034-9 Couplant: Hi-Temp 510oC; 2oz Tube (Material Safety Data Sheet)
Other Accessories  
TZ-24036 Temperature Sensor with 6' Cable