Tell-Tales are precision gauges that consist of two plates which overlap for part of their length. The bottom plate is calibrated in millimetres and the top plate is transparent and marked with a red hairline cursor in the form of a cross.
The Tell-Tales are fixed with screws and adhesive across the crack to be monitored. The Tell-Tale Plus is supplied pre-set at zero. After fixing, the temporary plugs are removed allowing each plate to move independently of one another.
Crack Monitoring
MONITORING TO +/- 1.00mm ACCURACY
As the crack opens and closes, or if vertical movement occurs, the cursor moves relative to the calibration scale. The opening or closing of the crack is then recorded on the record card supplied.
MONITORING TO +/- 0.1mm ACCURACY
For more accurate monitoring, Vernier, Dial or Digital Calipers can be used to measure the distances between the monitoring spigots. The distance between the spigots is then recorded on the record card supplied.
It is essential that products used for monitoring changes in crack width are quality precision instruments.
Great reliance is placed on the result of the monitoring and the user may be liable if inappropriate remedial work is recommended based on the results of imitation products of inconsistent quality.
- Suitable for internal and external use
- Record cards supplied with each Tell-Tale
- Calibrated in millimetres
- Manufactured in vandal resistant polycarbonate
Co-efficient of thermal expansion: 7.0 x 10-5 cm/cm° Centigrade for temperatures between –30° to +30°Centigrade.