Safety Wire

Tools Needed:

Safety Wire	Drill Press
Drill Bits	Cutting Oil
Wire Cutters	Wire Pliers

This guide will show you how to correctly use safety wire. Several organizations require safety wire including FAA, FIA, SCCA, NHRA, and many others.

Most safety wire ranges from .020 - .040 in diameter. For most applications it is composed of stainless steel or inconel, although copper and other metals can be used . The two main purposes of safety wire are:

1. Retain bolts and components from falling off the vehicle in the event of failure.
2. Prevent fasteners from backing off due to vibration or other environmental reasons.

Several chemical compounds as well as nylon lock nuts advertise the same claims. While these products are great at preventing back out, they do nothing to retain failed components. Also both products become ineffective at high temperatures.

The first step to safety wiring any item is drilling a hole for the wire to pass through. Due to corrosion issues I suggest only drilling stainless, titanium, or aluminum bolts. If those materials are not available I advise finding a pre-drilled bolt that was correctly treated post drilling. Regular bolts and nuts are pretty straight forward. You will need to secure them and drill the smallest hole that will allow your gauge wire to pass through them. While drilling you should use plenty of cutting fluid and go slowly. There are jigs available for this but I suggest you make your own vice jaws with small piece of soft wood and an extra bolt. Banjo bolts require a special procedure due to the fact they are hollow.

To drill a banjo bolt start by drilling a very shallow hole almost on one of the corners as show above in red. Next rotate the bolt 30 degrees and drill a slightly deeper hole as shown above in blue. Finally one more 30 degree turn. This time drill all the way through as shown above in chartreuse.

Below is a finished bolt.
Banjo Bolt

In this example we will assume you want to wire two bolts and a banjo fitting together. First measure the distance between all the mounting points. No point should be more than 5" apart and the total distance should be under 20". In this example all 3 points are 3" total. Take the total distance and multiply it by 3 to get the length of wire you need. So in our example I started with 9" of wire. Start by threading the wire through first bolt and bending it back on itself in the middle as shown below.

Using wire pliers twist the approximate distance to the next bolt together as shown in the next image. The number of twists you will need depends on the gauge of wire you are using. Usually the box the wire came in will be labeled. An easy way to count twists is to know how many twists each pull of your pliers makes. The set I use makes three twists per pull. Assuming I wanted 9 twists per inch and I had one inch to span, I would pull the handle 3 times. For two inches I would pull the handle 6 times.

Now thread one of the wire leads through the next bolt. You will want to do this in a way as to make the wire want to tighten the bolt not loosen it. Now twist the next segment leading up to the third bolt.

Now thread the wire through the last bolt and twist the remainder of your wire. About half an inch past the last bolt you can trim off the excess wire and bend the wire down on itself. The reason you pigtail the wire is to prevent stabbing yourself with it at a later time.

Here is a short movie that highlights the process.

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