Stainless Steel Safety Wire / Lockwire, MS20995C, Type 302/304 per ASTM A580, 1 lb Dispenser Can (Choose Diameter)

Specifications

Choosing a Diameter

If you are buying one can, buy 0.032″. It covers the large majority of motorsport and airframe work and is what most tech regulations assume. Go thinner only when the fastener spacing or the drilled hole forces you to, and thicker when the hardware is large enough that 0.032″ would be the weak link.

Typical Applications by Size

How to Safety Wire Properly

The principle that governs every installation: the wire must be loaded in tension by any motion that would loosen the fastener. If a bolt backing off would slacken the wire rather than pull it tight, the installation is wrong no matter how neat it looks.

• Work in pairs or groups. Wire each fastener to another fastener, or to a fixed anchor point. A wire that only ties a bolt to itself does nothing.
• Pull in the tightening direction. Route the wire so it leaves each bolt head on the side that resists loosening — for a standard right-hand thread, the wire should tend to pull the head clockwise.
• Keep the twist uniform. Guidance in AC 43.13-1B is generally around six to eight twists per inch for 0.032″ wire, with finer wire twisted a little tighter. Consistency matters more than hitting an exact coun — always follow the specific figure in your build or maintenance manual where one is given.
• Taut, not stretched. The wire should be snug with no slack, but stainless work-hardens as you twist it. Over-twisting is the most common cause of failure, and a wire that has been drawn down thin at the twist will fatigue and break in service.
• Finish the pigtail properly. Twist the tail three to four turns, cut it to roughly a quarter to half an inch, and bend it back toward the component so it cannot catch a
  hand, a glove or a brake line.
• Never reuse it. Safety wire is single-use. Once twisted it is work-hardened and will not take a second installation reliably.
• Keep the span sensible. Long unsupported runs between fasteners invite fatigue from vibration. If a gap is wide, use a heavier gauge or find an intermediate anchor.

The Dispenser Can

The wire ships coiled inside a sealed canister with a feed hole in the lid, so you pull off only what you need and the remainder stays clean, contained and tangle-free. Keep the lid on between jobs — loose safety wire that has been dropped on a shop floor picks up grit and becomes a contamination risk on anything you are about to close up. Because the wire is packaged by weight rather than length, the footages listed above are close approximations.

Why Safety Wire

Safety wire is the most positive fastener retention method there is. A locknut resists loosening by friction and a thread locker resists it by adhesion — both degrade with heat, vibration and
reuse. Safety wire is a mechanical restraint: the fastener physically cannot back out far enough to leave the joint, because a wire tied to something else is in the way. That is why tech inspectors ask for it, and why it remains mandatory on drain plugs, caliper bolts and critical flange hardware in most race series and on certificated aircraft.

It is also the only retention method that gives you a visual record. A properly wired fastener that has moved will show slack wire, so a walk-around before a session tells you something a torque wrench cannot.

Beyond the Race Track

The same wire and the same technique are used well outside motorsport:

• Road racing and motorsport — the mainstay of scrutineering compliance: sump and gearbox drain plugs, oil filters, caliper and hub hardware, turbo and exhaust flanges, catch tank and dry sump fittings.
• Experimental and certificated aviation — control system hardware, engine accessories, turnbuckles and inspection panels, where safety wiring is a required practice rather than an option.
• Drones and UAS — securing gimbal, payload and motor mount hardware on airframes that vibrate continuously and cannot be inspected mid-flight.
• Robotics and automation — retaining fasteners on high-cycle arms and linkages where thread lockers fail on repeated service intervals.
• Maritime — shaft couplings, rudder and steering linkages, and rigging hardware. Stainless is the right material choice for continuous salt exposure.
• Light industrial and machinery — guard fasteners, press and stamping tooling, and any inspection-critical joint where a visual check needs to be unambiguous.
• Tamper evidence — sealing enclosures, meters and containers, where a broken wire is proof of access.

Type 305 and Type 316 on Request

We stock type 302/304 to MS20995C. For aerospace programs or heavy marine service, type 305 and type 316 stainless are available to order, along with other diameters and bulk spool quantities. Type 316 adds molybdenum for markedly better pitting resistance in chloride environments; type 305 offers lower work-hardening for applications involving severe forming. Call 1-844-F1PARTS (1-844-317-2787) or email sales@formularaceparts.com with the material, diameter and quantity and we will quote it.

You Will Also Need

Safety wire pliers do the twisting for you — clamp, pull the knob, and the jaws spin the wire at a consistent rate. Twisting by hand with regular pliers is possible but produces uneven twists and work-hardens the wire unpredictably. A pair of proper wire cutters matters too, since stainless will destroy edges meant for copper.