G2 Gauge

Technical Specifications

Overview of the G2 Crack Gauge

The G2 crack gauge is used to measure and record the spreading development of expansion joints, crack edges, and/or generally the spreading development of gaps between two elements.

This measured change is represented graphically by a line that shows the maximum and minimum movement amplitudes. A removable, ventilated protective cover prevents condensation and protects the device. The cover can be sealed, and a corresponding seal is supplied with the gauge to secure the device.

The gauge consists of a base plate and a tension plate, which are fixed on either side of the crack.

During movement, the slider pulls an arm that has a graphite lead at its end. This is held under pressure by a polycarbonate disc.

The trace of the lead corresponds to three times the movement of the vernier. After observation, the trace can be removed with alcohol to reuse the gauge.

Fixing G2 Crack Gauges

• Adhesive fixing: Use the provided adhesive strips if the surface is smooth, clean, and dry. If the surface is not completely flat and has irregularities, the mounting should be reinforced with a two-component adhesive.
• Mechanical fixing: For difficult substrates that are crumbly, dusty, damp, uneven, or in cases where the installation temperature cannot be maintained, mechanical mounting should be preferred. Impact anchors are provided for mechanical mounting of the G2 gauge.

Reading the Measurements

Reading using the vernier principle:

• The upper scale on the movable arm is divided into millimeters from 0 to 40 mm and forms the measurement scale
• The lower, fixed scale with the triangle is the vernier, which provides accuracy of 0.1 mm (10 divisions of the vernier correspond to 9 mm on the measurement scale)

a) Reading the millimeters

The vernier triangle is located between two lines on the measurement scale. The number of millimeters corresponds to the scale marking to the right of the vernier triangle: In the example, it is 20 mm.

b) Reading the decimal numbers

Look for a line on the vernier that aligns with a line on the measurement scale. In the example, the 7th division of the vernier coincides with the 27th division of the measurement scale. This means the decimal value is 7/10 mm.
The reading value in the example photo is therefore: 20.7 mm.