Radial-Lok®
A unique hole-filling, high strength blind fastener
With its uniform radial expansion throughout the entire fastener grip, Radial-Lok® is uniquely suited to offer both enhanced fatigue strength and lightning strike damage protection.
Key Features
- Uniform radial expansion throughout the entire length of the clearance fit hole
- Interference fits to .006³
- Enhanced fatigue life
- Better lightning strike protection
- Eliminates costly hole preparation
- Clearance fit before installation
- Easy one-sided installation
- High clamp-up
- Large blind-side upset
- Tighter joints
- Ideal for aluminum and composite applications
- Available in 3/16³ through 3/4³ diameters, including oversizes
- .100³ grip accommodation
- 7-degree blind slope capability



Find a Distributor
Use the link to find an authorized Monogram Aerospace Fasteners distributor near you.
The most versatile blind fastener for a variety of applications
The ability of the Radial-Lok® to expand (.002³ to .006³) 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 .003³ hole tolerance, these benefits are achieved without the costly preparation of close tolerance or tapered holes required by some fasteners.
Radial-Lok®’s unique characteristics make it the most versatile blind fastener for a variety of applications in both composite and aluminum structures. It is completely compatible with graphite and is not subject to galvanic corrosion. In addition, Monogram’s drive nut system greatly simplifies the installation of Radial-Lok® fasteners.
Comparative photos show the benefits of the Radial-Lok® fasteners unique hole-filling properties as compared to a conventional fastener. Bands shown are made visible by viewing a bi-refringent plastic through polarizing filters.

