Blog

An arc-second is a measurement unit for angle. It is often used in describing level and plumb. 1 arc second = 1/3600 degree = 0.000278 degree =0.0000048 inches/inch =0.0048 mils/inch = 0.0048 mm/m 1 degree = 17.347 mils/inch 1 mil/inch = 1 thou/inch = 1 mm/m (The metric-imperial relationship is purely a coincidence!) A high […]