Avongard Plus Tell-Tale Crack Monitor
Avongard Tell-Tales are precision gauges uses to monitor movement of a crack, horizontal or vertically on a flat surface. The monitor that consist of two plates which overlap for a part of their length. The bottom plate is calibrated in millimeters and the top plate is transparent and marked with a hairline cursor in the form of a cross.
Compared to the Standard, the Plus Tell-Tale has a larger scale allowing for monitoring of cracking up to +/-25mm in the horizontal plane. It also has spigots allowing for simultaneous finer precision monitoring using digital or vernier calipers.
Monitoring Crack Movement to +/- 1.0 mm accuracy
As the crack opens, 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 crack record sheet supplied
Fixing the Tell-Tale
The Tell-Tale is fixed across the crack using screws and plugs and/or adhesive (sold separately)
Fix the Tell-Tale over the crack with the vertical 0 line on the calibration scale parallel with the crack to be monitored.
Ensure the plate with the engraved AVONGARD name is on the right hand side of the crack.
Remove the four pre-set pegs. If the crack opens or closes the cursor moves relative to the calibration scale. The opening or closing of the crack can then be recorded on the record sheet (supplied with each crack monitor)