The High-Low Detector, or Rolling Straight Edge, is used to measure planeness of pavement surfaces, such as highways, airport runways, bridge decks, etc. Requires only one operator to detect, register, and dye mark high and low areas that need to be ground down or filled.
Operator has full view of variations which are magnified 16 times, on a vertical scale graduated in 0.125" (1mm) increments, so that magnified readings range up to 0.25" (6.4mm), high or low.
Frame is constructed of rectangular aluminum and wheels are provided, one front and one rear with precision ball bearings and neoprene tires for support. Scraper blades keep wheels clean to maximize accuracy. Includes wheel stands for stabilizing during calibration, transport and storage. There is provision for checking wheel alignment. A steering handle is provided for easy positioning and movement, and provides a button for dye discharge. The 16 ft. long model incorporates aluminum reinforcing riveted along both sides of the frame for added support and rigidity.
Marking dye is used to mark high and low areas on pavement. Dye can mount is designed for 12 oz. (340g) aerosol cans.