The OSHA and ANSI/ITSDF 856.1-2009 standards for the inspection of forks in service require that forks with 10% wear to the blades be removed from service.Fork calipers are used to determine wear. The outside jaws are used to set the calipers (Fig. 1 ). The inside jaws measure 10% less than the outside jaws.
To inspect a fork, set the outside jaws by lightly closing the calipers against the back height (shank) of the fork (Fig. 2).
Note: distortion may occur if force is used in closing the calipers. Hold the calipers square at 90 degrees for accurate measuring.
When the calipers are set to the back height thickness, move them to the blade of the fork. If the inside jaws (Fig. 3) slide over the blade at any point between the heel and the beginning of the taper, the fork should be removed from service.
Note: Full tapered forks should be measured within 2 inches of the heel.