Comet Spherometer - Superior 2.5 Inch - 40mm Brass Dial Head - 3 Stainless Steel Legs Radius Gauge

Economy spherometer instrument used to measure the radius of curvature of a sphere or curved shape, most commonly of a lens. Used in optometry. Features a fine screw moving in a nut on a three-legged frame forming a triangle. Based on the principle of screw. Consists of a base circle of three legs, a central leg that can be raised and lowered, and a reading device. Made of high quality brass and stainless steel. Built to last. Measurements: - 40mm diameter dial head - 1mm pitch with 0.01mm count - 10-0-10mm vertical main scale - 10mm on prongs with micrometer scale with 100 divisions.