Tech Tuesday: Proper Safety Wiring
NEWS January 10, 2012
Photo by Brian J. Nelson
Imagine a beautiful crisp morning, you’re getting motivated to go out on track, now the only thing left to do is make it through technical safety inspection! Do you find yourself asking, did I safety wire my motorcycle right? What are the regulations this organization has to make it out on track? If thoughts like this have ever put a damper on your track experience, then read on. In this Tech Tuesday article, AMA Pro Racing would like to help you understand why it is important to have certain items wired correctly. We would also like to give insight from the experts at the Federal Aviation Administration on what the proper safety wire techniques are.
Everyone has their own methods of safety wiring, which are all variations, some proper and some improper, of ways to safety wire and secure one item to another. The FAA has some of the strictest standards set on safety wiring and securing items, and AMA Pro Racing has adopted standards of safety wiring based upon the plethora of information that has been produced by the FAA.
The first step, as always, is to get the proper protective equipment and tools. As far as safety equipment is concerned, safety glasses and gloves should be sufficient for this task. The proper tools should consist of but not limited to, cutters, drill with properly sized bit, something to hold the bolt secure while drilling, safety wire pliers, torque wrench and a magnet. The second step is to select the proper material and gauge of wire that is needed for the application, and to get that information, you must look at the rules for the racing organizations that you are participating with. Every organization has their own set of guidelines and standards that apply to safety wire; the AMA Pro Road Racing standard can be found in our 2012 rule book on page 39, Section 3.6.d.
The FAA regulation guide notes that safety wire is not meant to obtain or maintain torque, but instead is a means of safety to prevent the disengagement of parts, so torque the item to be secured on the motorcycle to its proper values. If this item is going to be torqued to another bolt, ensure that the second bolt is torqued as well. Make a mark on the bolt you want to drill, if this bolt is to be secured in a chain of other bolts to another bolt, mark them in the same direction of alignment as the first. Number the bolts so that they can be placed back in the proper order after drilling. Now secure the bolts to something so that they will not move while you are drilling. Depending on your specific application, the recommended holes are as follows: wire diameter is .032, recommended hole diameter size is 0.060-0.080 inch.
After drilling the items, they should be installed back into the original positions that they were fitted for earlier. Cut the proper length of safety wire, which is usually two and a quarter times the whole length of what is to be wired. Install the safety wire through the first item to be wired. While twisting the wire, be cautions not to overstress the wire while tightening as it will make the wire brittle and more prone to breaking during vibration. While pulling on the safety wire pliers, the wire should be pulled taut and maintained under light tension to inhibit it from becoming loose and twisting in line. The proper recommended twist per length on the .032 wire that we are using in this example is 7-10 twists per inch. Safety wire should also pull against the item that is being secured in the direction that will tighten the assembly. When proper twist loops are acquired, ensure that the wire is taut to the next bolt or item to be secured, preventing the wire from rubbing and wearing on other items, which could weaken the structure of the safety wire. Secure the second loop of the wire to a hard point, secure the loop and complete with four to six complete turns .5 to .625 inches from the securing point. Cut the wire and fold it under the last few twists to keep any sharp edges from cutting anything.
Follow the same procedure as above for all of the other bolts that you have to secure, according to the stipulations set forward by the on-track organization that you are participating with. Following these simple tips for safety wiring can help make your trip to technical inspection a simple, fun part of your track-day experience.
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