JAMES C RAY
Engineers in Lynchburg, VA

6490950, Dec 10, 2002

Feb 15, 2001

09/783030

James C. Ray - Lynchburg VA
Tom Rankin - Hamilton, CA

Ray-Griffin, Inc. - Lynchburg VA
Robertson, Inc. - Milton

B21K 500

76119, 81436, 761011

A set of driver bits for Robertson screw fasteners includes driver bits ( ) whose shaft bodies ( ) have distinctive markings thereon corresponding to respective sizes of working tips ( ) 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 ( ) of some of the driver bits by plating the shaft bodies with zinc layers ( ) and then dying the outer surfaces of the zinc layers with color dye ( ). This coloring is carried out before the shaft bodies are connected to their respective working tips. Once the outer surfaces ( ) 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 another embodiment, the distinctive markings are surface-irregularity rings ( ) 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.