Nut and Bolt Safety Wire Drill Jig

This unique jig drills through the corner of the hex, making it ideal for drilling nuts as well as bolts. Full adjustability allows use on virtually any hex-head fasteners up to 1 1/16" (27mm) hex: SAE, metric, even Whitworth! Requires a 1/16" Drill Bit (Part No. 3746), sold separately. Not for use on reduced-hex nuts such as MS21042 Jetnuts or plumbing tube nuts. The hex size must be 1/8" (3mm) larger than the thread size to avoid drilling through the threads.

Tech Tip: Drilling through the corner of the hex means drilling at an angle to the surface. Even with a drill jig, the sideways pressure will tend to make the drill bit push towards the corner of the hex. This results in a very shallow hole. In extreme cases, the bit may even just cut a groove in the corner of the hex. For best results use a drill press and advance the bit VERY SLOWLY.

To minimize skipping and push-out, start a shallow pilot hole perpendicular to the hex face using a 1/8" drill bit with a standard 60° point angle. The 1/16" bit should then drill into the angled face where the lip (face) of the larger bit has drilled. Center-punch to minimize drill walking.

For more details, see Chapter 4 of Carroll Smith's Prepare to Win, "Drilling Offset Holes."