Gilson Concrete Crack Monitor HM-634
Monitoring widths of cracks in concrete building walls and floors, bridge arches and decks, and roads is easy and reliable with Gilson Concrete Crack Monitors. Designed for external and internal use, the monitors are affixed with user-supplied screws and adhesive. The overlapping upper plate is transparent and marked with a hairline cursor. The red cross-hair cursor is positioned over the crack. The white bottom plate measuring grid is marked in millimeters. Opening and closing of the crack is monitored in 1mm increments.
The HM-634 is vandal-resistant, clear polycarbonate, with a range of 25mm horizontally and 10mm vertically. Adjustment fixing slots for screws and 'extra-grip' contact surfaces ensure secure placement of the Monitor. After affixing, temporary zero preset pegs are removed so plates can move independently. Spigots on the ends of both plates enable exact measurement to 0.1mm with calipers. (Gilson recommends TSA-271 Digital Caliper.) Readings may be recorded on the included Crack Record Card. A second Crack Monitor may be positioned to monitor crack movement in three dimensions. The HM-637 Economy Crack Monitor is a simpler design with a range of 20mm horizontally and 10mm vertically. Mounting and monitoring procedures are similar, but there are no spigots for use with calipers and the mounting holes are not slotted. Readability is 1mm. The HM-635 Corner Adapter enables Crack Monitors to be used in corners with greater or less than 90° angles.
Optional HM-636 Crack Width Gauge assists those who survey and report on damaged buildings. Supplied with an ever-ready case, this durable acrylic Gauge is scaled to measure cracks up to 7mm and wider in corners and awkward locations.
Get Pricing
Get Information