To Measure Inside Radius

Inside Measurement Example

Here is the ARC MASTER IRG 3600, measuring a steel angle rolled with the leg out, therefore measuring it from the inside.

Arc segments or sweeps can only give you an approximate radius measurement of your work piece. You would need a large inventory of sweeps and lot space to store them in just to attempt to do what the Arc Master radius gauges can do.

The manufacturer offers a tolerance of +/- .5% or less on any indicated measurement. As an example, on a recorded radius of 10″, the accuracy would be within (10 x .005) = .05″ or less than +/- 1/16″. Or as another example, a radius of 120″ would be accurate to (.005 x 120″) = .6″ or less than +/- 5/8″.