OSI-Bolt animation


Traditionally, blind fasteners have been used in secondary airframe structure where joint loads are less severe than in primary structure. Solid shank fasteners are normally used in these highly stressed areas because of their ability to carry high shear and tensile loads.

The OSI-Bolt is a unique new fastening system specifically designed as a direct replacement for solid shank pin and collar systems; its shear, tensile and preload properties meet or exceed that of its pin and collar counterparts. Moreover, unlike two-piece fastening systems where two operators are required to work together on opposing sides of a structure to complete an installation, the entire OSI-Bolt installation is facilitated from one side of the structure, eliminating the need for a second operator.

Other OSI-Bolt design features include its demonstrated ability to be installed in high interference fit conditions (.006” in aluminum and .003” in steel) without losing sheet take-up and preload capabilities. Its large blind side footprint coupled with the industry’s highest preload make the OSI-Bolt suitable for both composite and metallic airframes. OSI-Bolts are available in fractional diameters 5/32” through 1/2”  and standard (1/64” & 1/32”) repair oversizes in Titanium, A286 cres and Inconel-718 materials to satisfy 95KSI and 112 KSI shear strength requirements. OSI-Bolts are directly interchangeable with standard and oversize pin & collar systems, can be installed with standard NAS1675 type tooling and, because the OSI-Bolt always breaks flush, there is no secondary shaving required. OSI series fasteners are tested to NAS1675 vibration endurance requirements and are highly resistant to vibration. Providing a full 1/16” (.0625) grip accommodation with +/- .015” capability the OSI-Bolt is also 7° backside slope and interference fit capable and is internally self-sealing to 100 PSI air.

  • Physical strength comparable to shear type pin & collar systems
  • 95 KSI shear and 112 KSI shear availability
  • Available in a variety of hex, tension, shear and protruding head styles
  • Diameters from 5/32 to 1/2”
  • 1/64” and 1/32” oversize availability
  • 1/16” grip with +/- .015” capability
  • “Vise-like” sheet take-up consistently provides the highest preload in the industry
  • Flat, uniform blind side footprint is the largest in the industry
  • Blind side formation is away from the edge of the exit hole
  • Seven degree blind slope capability
  • Interference fit to .003” in steel
  • Resistant to vibration
  • Ideally suited to composite or metallic applications
  • Lightweight titanium version available
  • Internally self-sealing to 100 PSI air
  • Easily adaptable to Monogram’s robotic Double Cylindrical Drive (DCD) system

For tooling information for OSI-Bolt fasteners please refer to the Installation and Inspection Specification download link under Product Details