G4 Gauge

Technical characteristics

• Dimensions: 140 X 220mm, Thickness: 24mm, Weight: 620g.
• Transparent polycarbonate so as to be inconspicuous.
• Intended for measuring variations in the width of cracks and damaged joints in inaccessible parts of structures: cathedral vaulting, tower block parapets, towers, bridges, silos, distant beams etc.
• Accuracy: 1/10th of a mm.
• It is attached at 3 points A, B, and C.

Detailed description of G4 gauge

The G4 gauge is intended for measuring variations in the width of cracks and damaged joints in inaccessible parts of structures: cathedral vaulting, tower block parapets, towers, bridges, silos, distant beams etc.

Reading the G4 gauge directly is possible from up to 50 metres away, (with binoculars or a surveying instrument)

This gauge is in transparent polycarbonate so as to be inconspicuous. The dial plate measures 140 X 160 mm and is 24 mm deep. The arm (20 X 60 mm), which can travel 55 mm, includes a lead and an oblong hole with a knurled screw to take up any play during installation. A needle movement of 5 minutes on the dial corresponds to a horizontal variation of 2/10th of a mm. One division of the indicator corresponds to a complete rotation of the needle, i.e. horizontal variation of 2.4 mm.

Installing the G4 gauge with the protective casing

We recommend installing a protective plastic casing if the gauge is exposed to the weather.
The casing is 33 X 28 X 6 cm; it has a self-adhesive strip around the edge 25 mm wide and 2 holes to ensure ventilation against condensation. During installation, we recommend making a hole at the lowest point of the casing to unable any moisture from infiltration or condensation to escape.

Installing the G4 gauge on a relatively flat surface

The mismatch between surface A and surface B is of a few millimetres.

Device for fixing the arm, supplied.

Installing the G4 gauge with double ball joint for a major mismatch

On any kind of structure, as planes A and B are mismatched to a significant extent this may produce 3 dimensional changes. Double ball joint device for fixing the arm.

A: Plane A , B: Plane B , C: Crack.