The Starrett 279 Inch Reading Fillet or Radius Gauge has 20 leaves to measure 0.02" to 0.40" concave or convex radii in woodworking, metalworking, machining, layout, and pattern-making applications. The 20 shaped leaves measure at any angle and are stamped with the radius size for accurate sizing. It measures concave or convex radii from 0.02" to 0.40", inclusive, in varied increments. It has an eccentric mounting that provides clearance between the leaf and the case when the gauge is open.
Nine leaves measure concave and convex radii from 0.020" to 0.10" inclusive by 0.010". Four leaves measure concave and convex radii from 0.125" to 0.20" inclusive by 0.025". One leaf measures concave and convex radii of 0.250". Three leaves measure concave radii only from 0.3" to 0.4" inclusive by .050" and three leaves measure convex radii only from .300 to .400 by .050"
The L.S. Starrett Company manufactures precision measuring tools, metrology and testing equipment, and saw blade products. The company, founded in 1880, is headquartered in Athol, MA.