Visu-Lok® Fasteners

The Visu-Lok family of fasteners, designed for use in metal structure, have addressed the need for cost effective one-sided fastener installation for decades. The basic design of the Visu-Lok is based on one of the oldest and time proven principles; the nut and bolt. However the Visu-Lok, unlike conventional nut and bolt pairings, is fully installed and verified from one side of the structure. With the ease of its one man, one-sided installation process the self-locking Visu-Lok forms a solid blind side head delivering high tensile, shear and fatigue values and guaranteed 20% minimum preloads. This simple installation process can be accomplished with either hand or compact power tools operating at standard air pressure levels and can be further simplified by adopting Monogram’s drive nut concept.

Visu-Lok II fasteners incorporate a disposable hex drive nut providing a positive fastener-to-tool engagement and eliminating the tendency for flush style fastener recesses to “cam-out” during installation. With the drive nut common to a variety of diameters and all head styles only two nose pieces are required to install the entire Visu-Lok II line. Nose pieces never wear out and the disposable magnetic drive nut stays on the discarded pintail after installation permitting easier retrieval and minimizing the chances of small pintails finding their way into F.O.D. critical areas. For automated or robotic assembly Visu-Loks can also be supplied with Monogram’s Double Cylindrical Drive (DCD) system. The DCD system provides a common tool interface regardless of head style, fastener grip, or diameter. And, because the interface and drive mechanism are cylindrical, there are no orientation problems!

All Visu-Lok drive styles are available in flush and protruding head configurations satisfying both shear and tension requirements. Visu-Loks are produced in a wide variety of materials including A286 Corrosion Resistant Steel, Alloy Steel, Aluminum, H-11, Inconel, and other nickel alloys. A wide variety of finish and lubricant combinations are available and defined in Monogram specification PLT5003.

• High strength fastening system available to 112 KSI shear
• Ease of installation further simplified by the drive nut concept
• Simple wrenching motion installation provides superior limited access capability
• Self Locking device resists loosening in severe vibration environments
• 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-Loks are covered by NAS standards and available in either unified or metric sizes
• Easily adapted to robotic or automated installation

Composi-Lok animation

Designed for use in composite laminates but equally well suited to metal structure, the Composi-Lok family of fasteners provides superior joint integrity. Composite laminates are capable of sustaining high loads but are subject to delamination when fastened with conventional fasteners. By providing a large blind side upset, hailed by some as the industry benchmark, Composi-Loks distribute bearing loads over a large area overcoming damage to the composite. The characteristic large blind side bearing area or “footprint” allows the fastener to impart very high clamp loads to the structure without damage to the composite. Structural integrity in severe vibration environments is assured by a patented locking feature. Proper installation can be achieved with simple and compact hand or power tools and verified from one side of the structure by measurement of the screw break-off position. Available in four distinct 75 KSI shear strength versions, all Composi-Loks are completely compatible with graphite and are not subject to galvanic corrosion. Composi-Loks are available in 5/32” through 3/8” diameters, including oversizes, and have a .050” operational grip range.

Composi-Lok II fasteners incorporate Monogram’s drive nut concept further simplifying the installation process by incorporating a disposable hex drive nut. The hex drive nut provides a positive fastener-to-tool engagement and eliminates the tendency for flush style fastener recesses to “cam-out” during installation. Since the drive nut is common to a variety of diameters and all head styles only three nose pieces are required to install the entire Composi-Lok line. Nose pieces never wear out and the disposable magnetic drive nut stays on the discarded pintail after installation permitting easier retrieval and minimizing the chances of small pintails finding their way into F.O.D. critical areas. Composi-Lok IIa and Composi-Lok3 variations also incorporate the drive nut feature.

All Composi-Loks provide these important advantages:

• Large blind upset eliminates composite damage
• Easy, labor saving one-sided installation further simplified by the drive nut concept
• Controlled clamp up - no gaps and tighter assemblies
• Completely compatible with graphite – available in titanium or cres materials to resist galvanic corrosion
• Visual locking feature resists loosening due to vibration
• Fuel tight sealing capability

Composi-Lok IIa fasteners, with their unique design characteristics, address the inherent thickness variations of composite material stack-ups. These common variations make proper grip measurement practices imperative to assure proper fastener performance and joint integrity. These concerns are minimized by the ability of the Composi-Lok IIa to function properly even when installed .050” beyond its prescribed grip accommodation.

While design considerations should be limited to the optimum performance characteristics of the fastener within its prescribed .050” grip range, the added assurance of joint integrity in limited out of grip conditions is available with Composi-Lok IIa. This extended grip capacity of .025” under minimum grip to .025” over maximum grip (for a total of .100”) with no composite damage and joint performance still in excess of guaranteed minimums makes the Composi-Lok IIa one of the most tolerant blind fasteners for composites on the market.

Composi-Lok3 is the newest cost saving design in the Composi-Lok series. With one of the most trusted names in aircraft assembly as its foundation, Composi-Lok3 delivers lower installed costs and increased productivity. *Designed to afford a flush to below flush break-off, the Composi-Lok3 requires no secondary saving, milling or grinding operations to meet aerodynamic flushness requirements. All the performance and reliability of our Composi-Lok is now available with a flush break-off. Without compromise on mechanical properties, high preloads or large blind side head formation, you save on tooling expense as well as the time and cost of shaving while productivity is increased with labor dedicated to other tasks.

*Composi-Lok3, with its controlled break-off, requires alternative means of post-installation inspection.

Radial-Lok animation

The ability of the Radial-Lok to expand (.002” to .006”) uniformly throughout the entire length of the hole greatly increases the fatigue life of the fastener and assures structural integrity under severe cyclic loading conditions in both aluminum and composite structures. With Radial-Lok’s .003” hole tolerance these benefits are achieved without the costly preparation of close tolerance or tapered holes required by some fasteners.

• Uniform radial expansion throughout the entire length of the clearance fit hole
• Interference fits to .006”
• Enhanced fatigue life
• Better lightening strike protection
• Eliminates costly hole preparation
• Clearance fit before installation
• Easy one sided installation
• High clamp up
• Large blind side upset
• Tighter joints
• Available in 3/16” through 3/4” diameters including oversized
• 100” grip accommodation
• 7 degree blind slope capability