Designed for use in composite laminates but equally well-suited to metal structure, the Composi-Lok® family of fasteners provides superior joint integrity. Today, Composi-Lok® is approved on virtually all composite airframe programs throughout the world. The new Composi-Lok3, in keeping with Monogram’s commitment to a lower installed cost design philosophy, is shave-free, providing the performance and reliability of our Composi-Lok® with the added benefits of a flush break.

Key Features

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

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Providing Superior Joint Integrity

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

Composi-Lok® II diagram with descriptionsComposi-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.

For automated or robotic assembly, Composi-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!

Composi-Lok IIa

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 shaving, 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.

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Part Numbers & Technical Drawings

Part FamilyPrefixMaterialHead StyleShank TypeSpecial FeaturesRated Shear StrengthTechnical Drawing Downloads
Composi-LokMBF2010TitaniumProtrudingNominalLow Profile Head75 KSI MBF2010-REV-AF.pdf
Composi-LokMBF2011TitaniumHexNominalReduced Head75 KSI MBF2011-REV-AH.pdf
Composi-LokMBF2012Titanium100 Degree TensionNominal-75 KSI MBF2012-REV-AI.pdf
Composi-LokMBF2013Titanium130 Degree ShearNominal-75 KSI MBF2013-REV-AG.pdf
Composi-LokMBF2110TitaniumProtrudingNominalLow Profile Head75 KSI MBF2110-REV-AD.pdf
Composi-LokMBF2111TitaniumHexNominalReduced Head75 KSI MBF2111-REV-AK.pdf
Composi-LokMBF2112Titanium100 Degree TensionNominal-75 KSI MBF2112-REV-AJ.pdf
Composi-LokMBF2113Titanium130 Degree ShearNominal-75 KSI MBF2113-REV-AP.pdf
Composi-LokMBF2120A286 CresProtrudingNominalLow Profile Hd75 KSI MBF2120-REV-W.pdf
Composi-LokMBF2121A286 CresHexNominalReduced Hd75 KSI MBF2121-REV-AC.pdf
Composi-LokMBF2122A286 Cres100 Degree TensionNominal-75 KSI MBF2122-REV-AC.pdf
Composi-LokMBF2123A286 Cres130 Degree ShearNominal-75 KSI MBF2123-REV-AA.pdf
Composi-LokMBF2130A286 CresProtrudingNominalInterference Fit90 KSI MBF2130-REV-L.pdf
Composi-LokMBF2132A286 Cres100 Degree TensionNominalInterference Fit90 KSI MBF2132-REV-J.pdf
Composi-LokMBF2133A286 Cres130 Degree ShearNominalInterference Fit90 KSI MBF2133-REV-J.pdf
Composi-LokMBF2134A286 Cres100 Degree Reduced ShearNominalInterference Fit90 KSI MBF2134-REV-H.pdf
Composi-LokMBF2140TitaniumProtrudingNominalLow Profile Hd / Ti Screw For Wt. Savings75 KSI MBF2140-REV-NR.pdf
Composi-LokMBF2141TitaniumHexNominalReduced Hd / Ti Screw For Wt. Savings75 KSI MBF2141-REV-NR.pdf
Composi-LokMBF2142Titanium100 Degree TensionNominalTi Screw For Wt. Savings75 KSI MBF2142-REV-NR.pdf
Composi-LokMBF2143Titanium130 Degree ShearNominalTi Screw For Wt. Savings75 KSI MBF2143-REV-D.pdf
Composi-LokMBF2310TitaniumProtruding, Low ProfileNominalFlush Break / No Shaving75 KSI MBF2310-REV-G.pdf
Composi-LokMBF2312Titanium100 Degree TensionNominalFlush Break / No Shaving75 KSI MBF2312-REV-L.pdf
Composi-LokMBF2313Titanium130 Degree ShearNominalFlush Break / No Shaving75 KSI MBF2313-REV-R.pdf
Composi-LokMBF2315Titanium130 Degree ShearNominalReduced Recess / Flush Break / No Shaving 75 KSI MBF2315-REV-F.pdf
Composi-LokMBF2322A286 Cres100 Degree TensionNominal-75 KSI MBF2322-REV-NR.pdf
Composi-LokMBF3003TitaniumProtrudingNominalLow Profile Hd75 KSI MBF3003-REV-W.pdf
Composi-LokMBF3004TitaniumHexNominalReduced Hd75 KSI MBF3004-REV-V.pdf
Composi-LokMBF3005Titanium100 Degree TensionNominal-75 KSI MBF3005-REV-AC.pdf
Composi-LokMBF3006Titanium130 Degree ShearNominal-75 KSI MBF3006-REV-AC.pdf
Composi-LokMBF3008A286 CresProtrudingNominalLow Profile Hd75 KSI MBF3008-REV-M.pdf
Composi-LokMBF3010A286 Cres100 Degree TensionNominal-75 KSI MBF3010-REV-P.pdf
Composi-LokMBF3011A286 Cres130 Degree ShearNominal-75 KSI MBF3011-REV-R.pdf
Composi-LokMBF3012TitaniumProtruding1/64 OversizeLow Profile Hd75 KSI MBF3012-REV-F.pdf
Composi-LokMBF3013Titanium130 Degree ShearNominalCrown Head75 KSI MBF3013-REV-H.pdf
Composi-LokMBF3015A286 CresProtruding1/64 OversizeLow Profile Hd75 KSI MBF3015-REV-E.pdf