Composi-Lok and Visu-Lok Tooling – A Guide to Specialty Blind Structural Fasteners

• March 22nd, 2024
• Categories: Uncategorised

Aircraft structures such as wings, flaps, tails, etc., must be structurally sound for thousands of flights. Each aircraft must withstand temperature changes, weather fluctuations, and high air pressure from ascent to descent. This is where fasteners such as Composi-Lok and Visu-Lok are so critical to aerospace fasteners projects. 

With high shear, tensile, fatigue, and self-locking capabilities, the Visu-lok Blind Fastening System is unlike conventional nut and bolt applications. Likewise, Composi-Lok has also become the industry benchmark for distributing bear loads over a large surface area and overcoming composite damage.

What makes Composi-Lok and Visu-Lok tooling so critical for aircraft modifications and repairs? This blog will delve into their key purpose and features, as well as how they have revolutionised the aerospace field.

Definition of Composi-Lok and Visu-Lok Tooling

What are Composi-Lok and Visu-Lok tooling, and what are the stand-out features for building aircraft? Let’s delve into these aerospace fasteners right now!

Visu-Lok Tooling

The Visu-Lok blind system, originally developed by Avdel in the UK, used standard installation tools at standard air pressure levels. The bolt can be completely installed and verified from one side of the structure, forming a solid blindside head with minimum preload levels guaranteed. The Visu-lok family includes the Visu-lok 2, which uses a disposable dry nut to install 2 two nose pieces for all fastener sizes.

A tapered version of Visu-lok suits severe fatigue applications such as fixed, rotary wing, commercial and military aircraft, offering the highest possible fatigue life, high preload values, and positive self-locking characteristics.

Composi-Lok Tooling

As an industry standard for the blind fastening of composite joints, Composi-Lok is designed for use in composite laminates and equally metal structures. Providing superior joint integrity, this family of fasteners is approved on all composite airframe programs worldwide.

Types of Composi-Lok and Visu-Lok Tooling

Composi-Lok tooling

There are various types of aerospace fasteners and tools available to install Composiloks, starting with hand tools to pistol Pneumatic tooling including offset and right angle installation tools. There is also removal tooling available. For more information, contact support@aft.systems for a competitive quote on our fasteners and tooling.

Visu-Lok tooling

Similar to the Composilok tooling, there are various types of installation and removal tooling available that suit Visulok fasteners. Hand tools, Pneumatic tools such as pistols, right angle and limited access are examples available. For more information, contact support@aft.systems or Applied Fasteners and Tooling  

Features of Composi-Lok and Visu-Lok Tooling

With high tensile, shear, and fatigue values, what are the beneficial features of both Composi-Lok and Visu-Lok aerospace fasteners?

Visu-Lok Tooling

• High-strength fastening system is available for 112 KSI shear.
• Simple wrenching motion installation provides superior limited-access capability.
• Self-locking devices help to prevent loosening in settings with severe vibration.
• Various finishes and lubrication options are on the market, defined in Monogram specifications PLT5003.
• It is a one-man, one-sided installation process that delivers 20% minimum preloads.
• Self-inspecting – installations are fully verified from one side of the structure.
• Available in a wide range of materials, sizes, and head styles, including oversize and close tolerance interference fit configurations to suit most applications.
• Visu-Lok tooling is covered by NAS Standards and is available in either unified or metric sizes.
• Visu-Lok tools can be easily adapted to robotic or automated installation.
• Ease of installation. Making use of common installation tools as standard air pressure levels, Visu-Lok fasteners are available in a wide range of materials such as Alloy Steel, Aluminium, H-11, Corrosion-Resistant Steels, Inconel Nickel-Chromium Alloy, and Titanium. 

Composi-Lok

• Visual-locking feature resists loosening due to vibrations
• Includes a fuel-tight sealing capability.
• Completely compatible with graphite and available in titanium or CRES materials to resist galvanic corrosion.
• Available in four distinct 75 KSI strength versions, all Composi-Lok tools are compatible with graphite and not subject to galvanic corrosion.
• Available in 5/32″ through 3/8″ diameters and have a 0.05″ operational grip range.
• A large, blind upset eliminates the risk of composite damage.
• Controlled clamp-up – no gaps and tighter assemblies.
• The drive-nut concept further simplifies easy, labour-saving, one-sided installation. 
• Proper installation can be achieved with simple and compact hand or power tools, verified from one side of the structure by measurement of the screw break-off position.

If you want to learn more about fasteners and tooling and why they are essential to critical applications in space, transport, defence, military, and other strength-reliant industries, check out our markets.

Composi-Lok II

Composi-Lok II fasteners incorporate Monogram’s drive nut concept, simplifying installation using a disposable drive hex nut. This provides a positive fastener-to-tool engagement and eliminates the tendency for flush-style fastener recesses to “cam out” during installation.

Only three nose pieces are required to install the entire Composi-Lok line. As these nosepieces never wear out, this minimises the chances of small pintails finding their way into F.O.D. critical areas.

Visu-Loks can be supplied with Monogram’s Double Cylindrical Drive (DCD) System for automatic or robotic assembly, providing a common tool interface regardless of fastener grip, head style, or diameter. There are also no orientation issues due to the cylindrical interface and drive mechanism. 

Composi-Lok IIa

Do you need a heavier-duty fastener? With unique design characteristics, Composi-Lok IIa addresses the thickness variations of composite material stack-ups.

Proper grip measurement practices are essential for proper fastening performance and integrity, and the Composi-Lok IIa functions well even when installed .050″ beyond its prescribed grip. With a total of a .100″ grip with zero composite damage and joint performance still in excess, this is one of the most tolerant blind fasteners on the market!

Composi-Lok3

As the latest cost-saving design, the Composi-Lok3 is a trusted name in aircraft assembly as its foundation. Delivering low installation costs and increased productivity, this fastener requires no secondary shaving, milling, or grinding operations to meet aerodynamic flushness requirements.

The Composi-Lok3 does not compromise on its mechanical properties, high pre-loads, or blind side head formation, saving your tooling expenses and time and allowing you to dedicate labour to other tasks.

Are you searching for components that support Monogram tooling and enhance your tool control kit? Applied Fasteners and Tooling supplies tools and fasteners from a familiar custom manufacturer. 

Components of a Composi-Lok and Visu-Lok Tool Kit

What are some examples of the components available in the aerospace application tool kit? Let’s explore both Visu-Lok and Composi-Lok options.

Alternative Monogram Blind Bolts

Radial-Lok Animation

The Radial-Lok fastener can expand uniformly (.002″ to .006″) throughout the entire hole length, increasing the fatigue life of the fastener. This blind bolt fastener assures structural integrity under severe cyclic loading conditions in composite and aluminium structures. 

With a .003″ hole tolerance, benefits achieved without costly preparation include tighter joints, high clamp up, large blind side upset, easy one-sided installation, clearance fit before installation, improved fatigue life, and interference fits .006″. 

Other advancements include better lighting strike protection, 100″ grip accommodation, 3/16″ through 3/4 diameters, oversized, and a 7-degree blind slope capability. 

OSI-Bolt

As the only blind bolts capable of equivalent usage with solid shank bolts, these offer a full 1.5D bearing area. The OSI-Bolt is a direct replacement for solid shank-pin-and-collar systems, delivering strength and advantages of the one-sided installation and flush break-off. This offers cost savings for metal and composite structures.

Expect 95 KSI shear and 112 KSI shear availability, diameters from 5/32” to ½”, 1/64” and 1/32” oversize availability, a 1/16” grip with a +/- .015” capability, seven-degree blind slope capability, interference fit .003” in steel, resistance to vibration, suitability for composite or metal applications, and more.

Consider exploring the uses of cable tie mounts if you’re interested in learning more about how fasteners and tooling can improve your aerospace projects.

Applied Fasteners and Tooling – Specialised Aerospace Fasteners

Looking for Composi-Lok or Visu-Lok tools? Applied Fasteners and Tooling help you find what you need for aircraft maintenance and repair.

Committed to maintaining a high standard of service as distributors of fasteners and tools for the Aerospace, Military, Defence, Space, Marine, Industrial, Mining, Transport, and Motorsport markets, we adhere to the AS9120 Quality System. We ensure supplier performance, on-time delivery, and quality for our aerospace fasteners and tooling.

Contact us today for a competitive quote if you’re looking for cable management tooling, Avibank Ball Lok Pins, check gauges, pneumatic installation or removal tooling.