SET OF DISTINGUISHABLE ROBERTSON DRIVER BITS

摘要

A set of driver bits for Robertson screw fasteners includes driver bits (10a-d) whose shaft bodies (12a-d) have distinctive markings thereon corresponding to respective sizes of working tips (14a-d) of the driver bits. These distinctive markings are consistent throughout a family of sets. In one embodiment the distinctive marking are different colors, with each different color corresponding to a working-tip size. The colors are applied only to shaft bodies (36a-d) of som e of the driver bits by plating the shaft bodies with zinc layers (22) and then dying the outer surfaces of the zinc layers with color dye (24). This coloring is carried ou t before the shaft bodies are connected to their respective working tips. Once the outer surfaces (20) of the shaft bodies are thusly colored, the respective working tips are swaged to the shaft bodies to thereby form color-coded Robertson driver bits. In anoth er embodiment, the distinctive markings are surface-irregularity rings (32) extending about the elongated shafts, with the least number of rings corresponding to the smallest size working tip and the most number rings corresponding to the largest working tip.