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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