Safety Wire: Techniques for Maximizing Proper Tension

Blog_AEROInc_ManVsPlane_2015_08Aug_Article18_Masthead_Final

Safety wire is a great addition to any engine compartment to help tighten hardware and is also used during the process of changing your oil and oil filter.

A common issue that arises when installing safety wire is that since the manual skill required to implement traditional safety wire is easily learned, the techniques required to maximize the tension of the safety wire (e.g., in which direction the tension should be exerted, the direction of twist, proper angles for securing multiple fasteners, proper twists per inch, which type of wire to use, etc.) are often ignored by non-formally trained technicians who use safety wire for their projects.

We firmly believe that the techniques needed to tie safety wire can be acquired with the proper information and practice. Safety wire  is a type of locking device that prevents fasteners from loosening or falling out due to vibration and other forces. The presence of safety wiring may also serve to indicate that the fasteners have been properly tightened.

Safety wire is available in a variety of gauges and materials, depending on the application. In aircraft applications, stainless steel wire is used. Typically, the wire is threaded through a hole drilled into a fastener or part, then twisted and anchored to a second fastener or part, then twisted again.

If you use safety wire properly, then you will be able to secure any nut, bolt, etc. on your aircraft so that vibration will not cause it to loosen during operation.

Choosing the Correct Plier

The easiest way to install safety wire to your aircraft is by using safety wire pliers. A new product that we highly recommend is the Milbar®  7W TigerWave vestiti corti da cerimonia per ragazze Safety Wire Twisters. The 7W TigerWave has some great features that make using this safety wire twister a true joy. It features a “smooth wave grip” to prevent nicks and scratches on the safety wire as the previous serrated grip used to cause. FOD (foreign object debris) prevention is always a major concern when installing safety wire so Milbar has included a cushion throat to catch any debris that falls during this process.

We will go into detail about certain kinds of safety wire pliers throughout this article. Safety wire pliers come in three common sizes: 6, 9, or 12 inch. Along with the different options for sizing you can choose whether to use a standard or reversible twister as well.

Blog_AEROInc_ManVsPlane_2015_08Aug_Article18_Body_CommonWireTwisters_Final

Standard twister pliers come in left or right handed versions depending on which way you prefer to twist the safety wire. When choosing a plier you will also come across an automatic return or manual return. The automatic return features a spring that retracts the twist rods to ease and speed up the work, whereas, the manual return does not.

Another nice option to have on your pliers is the cushion throat which catches clipped wire ends and prevents FOD within your aircraft’s engine compartment. Smaller length pliers offer a tapered or diagonal nose as well to fit the users preference.

You can also purchase a reversible twister which allows the option to use both left or right handed twisting. Offering two nose configurations, tapered and diagonal, gives the user flexibility amongst projects.

As the standard twister pliers have, the reversible models also have the automatic spring return as well as the cushion throat to catch loose clippings as they fall.

 

Considerations Before Installing

AVWeb.com gives some great procedures to consider before installing:

  • Use new safety wire for every application.
  • Do not tighten so much that vibration could break the wire.
  • Do not over-twist; twists should be tight and even.
  • Create a “pigtail” of ¼” to ½” at the end of the wire run.
  • Tighten castle nuts to the low side of the specified torque range unless otherwise specified.
  • Apply the wire so that any pull from the wire tightens the nut, not loosens it.

Installation of Safety Wire

Once you have chosen the correct safety wire plier for your specific job, you will want to begin by grabbing the two loose ends of the wire and locking the plier on these two ends. Once the two ends are firmly grasped by the nose of the pliers, pull the knob and release the pliers with your opposite hand, allowing the pliers to twist the safety wire. Perform this action until the wire is securely twisted as shown in the video below.

When using the Double Twist Method (Aerospace Standard AS567) you will want to be sure to understand a few key points. First, the maximum span of safety wire between tension points is only 6”, so do not stretch it too far and do not use more than 24” per application. Second, when looping the wire around the outside of a fastener, always route under the wire protruding from the hole. Third, do not make your pigtail too long; it should be no more than ¾”. Lastly, the number of twists per inch (1 twist= ½ complete turn) depends upon wire diameter:

  • 0.020”to 0.025” diameter= 8-14 twists
  • 0.032″ to 0.041″ diameter= 6-11 twists
  • 0.051″ to 0.060″ diameter= 4-9 twists

 

Whichever safety wire plier you choose, be sure to always follow the standards. These proven methods have been tested over multiple decades and can be the difference between you flying safely or not.

Please give this information a share using our social sharing buttons!

 


References:

http://www.avweb.com/news/maint/191176-1.html
http://imperial-tools.com/content/milbar-wire-twister
http://www.crawfordtool.com/wire%20twister.html
https://en.wikipedia.org/wiki/Safety_wire
http://www.milbar.com/
Similar posts
  • Engine Accessories: The Unsung Heroes... When it comes to the firewall forward section of the aircraft, most pilots only consider the engine. But engine accessories and other additional components can influence aircraft safety, efficiency, and cost. So for this blog we are going to focus on the unsung heroes under the cowling – the accessories. [...]
  • Aircraft Oil Change, Say What Again? My idea of changing the oil in something is to show up at one of the many instant oil change places, sit down, read a book, and pay when I’m finished.  So, when I was approached by my dad to help him change the oil in his airplane, naturally, my response was [...]
  • The Aircraft Battery Battle: Your Que... Selecting the proper aircraft battery involves a number of questions… How long will the battery last? What price should you pay for a good battery? Which battery company should you trust? We will help you solve these questions and make the correct decision, right now. [...]
  • 1 Way to Eliminate your External Powe... Have you ever wanted or needed to change your aircraft’s anti-collision lights? These lights can be a hassle due to external power supply complications. Aircraft engineers, technicians, and pilots can greatly benefit from using aircraft lights that do not use an external power supply. [...]
  • 2 Ways to Battle Aircraft Corrosion Your aircraft is a large metal object that can be affected by numerous factors such as rapidly changing temperatures, rain, sleet, hail, salt water, and other related issues. All of these can lead to one major problem for the metal on your aircraft, corrosion. [...]

No Comments Yet

Have something to add? Commenting puts you in the pilot’s seat!

Join Over 12,000 Satisfied eNews Subscribers, Now!
We provide unique content related to aircraft parts, like: how-to and advice articles, company and industry news, events, special offers, promotions, and featured products. All delivered directly to your inbox. Subscribe today for free!
We hate spam. Your email address will not be sold or shared with anyone else.

Connect With Us

Upcoming Events

no event