HI-SHEAR Fasteners are manufactured by the HI-SHEAR CORPORATION, subsidiary of LISI AEROSPACE, a manufacturer of advanced aerospace fasteners and installation equipment used in space, military and commercial vehicles. Made from a variety of alloys and metals, these fasteners are designed to withstand hi-shear and tension values as well as extreme temperatures and high-vibration stress. A wide range of fasteners are available for different functions under different trademarks such as HI-LOK™, HI-LITE™ (HST™) or HI-TIGUE™ (HLT™) briefly presented below and are extensively used today in aerospace and other applications. The company also offers several other aerospace fasteners, such as the HI-TORQUE™, HIi-SET™, pull-stem and the pull-in, lock-bolts with tensile and shear strength/blind lock-bolts and recess fasteners in different materials and geometries.
Several HI-SHEAR HI-LOK™ (HL™) and HI-LITE™ (HST™) fasteners can be used as alternates to EN6114 series which together with their EN6115 counterparts are commonly used on Airbus A320, A330, A350 and A380 aircraft. Airbus A320/ A330 aicraft commonly use the alloy steel version of the EN6114 series and the Titanium series indicated by the V and T coding. The new A350 and A380 designs incorporate Inconel material deliniated by the L and M coding.
HI-SHEAR HI-LOK™ (HL™) Fasteners
The HI-SHEAR HI-LOK™ (HL™) one side installation fastening system with built-in preload control is the second most used in aircraft structural assembly after the solid rivets MS20470 and MS20426. Made from metals and alloys such as titanium, Inconel, temperature alloy, aluminum and alloy steel the HI-LOK™ are the industry standard for high strength permanently installed airframe fasteners. The HI-LOK™ fastening system includes a rivet pin (similar to a screw but with additional advantages) and a collar (similar to a nut). The HI-LOK™ rivet pins are available in different head styles, such as flush shear, protruding shear, flush tension and protruding tension while HI-LOK™ collar styles include the standard size as well as oversize, sealing, swage and self-aligning. The HI-LOK™ fasteners work well in restricted-access applications. Delivering high strength controlled preloaded system, the HI-SHEAR HI-LOK™ rivet pins are the original and versatile solution for strong and reliable assemblies. With a wide range of shapes, materials and coatings, they are suited for most of structural assemblies and are still commonly used in the aerospace industry for clearance, transition and low interference fit throughout the airframe (metallic and composite), from wings to fuselage, in engine fairings, and more. The HI-LOK™ series includes several type of rivet pins and collars, depending of the desired application with the HL18, HL19, HL20 and HL21 series being the most used ones. The HI-LOK™ rivet pins can be divided for use in tension and shear applications. The tension rivet pins, with greater heads than the shear pins, are selected when the main load applied is tension while the shear rivet pins when the shear is the dominant load. Rivet pins can be further divided in those with protruding or countersunk head. For example, the HL18 series realte to shear protruding hed rivet pins, the HL20 are tension protruding head rivet pins, the HL19 are shear countersunk head rivet pins and the HL 21 are countersunk head pins.
The main reasons/benefits of using this type of fasteners include:
1. Higher tension and shear strength, the material used and the geometry of the fastener provides the best properties regarding strength. Suitable for shear and/or tension applications, on plain or sloped surfaces
2. Lightweight fasteners, the HI-LOK™ system offers the best relation between weight and strength regarding the assembly between two elements. Better that the use of screws and nuts.
3. Easy and quick assembly, with the specific tools the assembly time is must lower that the rivet or screws/nut assembly time. The assembly is very easy with no complex steps and the final assembly is always perfect with no defects. Suitable for clearance, transition and low interference fit installation.
4. Good stress concentration factor, the specific geometry of the pin element provides the hole with an increase in fatigue life, much better that if we use the screw/nut system.
5. Fastener cost, accessible and cost effective element in the installation on the aircraft.
6. Correct torque application, the collar property gives us the guaranty that the correct torque is applied to the assembly, removing the problem of vibration, strength and fatigue of the pin itself.
7. Wide variety of materials and coatings for installation in all structures.
HI-SHEAR HI-LITE™ (HST™) Fasteners
The HI-LITE™ (HST™) fasteners are lightweight threaded fasteners designed for multiple purposes. The HI-LITE™ pins are available in metals and alloys including alloy steel, temperature alloy, aluminum and titanium. Head styles offered include protruding shear, reduced flush shear and protruding tension. The HI-LITE™ collars offered are basic, self-sealing and self-aligning for shear and tension applications. Materials available are stainless steel and titanium. Sizes are standard and oversize.
The HI-LITE™ series pins consist a direct evolution of HI-LOK™ rivet pins and can replace equivalent parts for improved weight saving. Combined with HI-LITE™ nuts and collars, they provide up to 13% weight saving compared to the previous HI-LOK™ generation. Both HI-LOK™ and HI-LITE™ rivet pins are also available with ASTER recess (HSTR pins) for an improved recess that prevents failure during the assembly process, especially suited for clearance fit assemblies of composite structures.
HI-SHEAR HI-TIGUE™ (HLT™) Fasteners
HI-TIGUE™ (HLT™) pin series are also offered featuring improved fatigue benefits by combining the hole-improvement qualities of the HI-TIGUE™ pins and the consistent preloading qualities of the HI-LOK™ collars.
The P/N of HI-SHEAR rivet pins is composed of sequencing letters and numbers indicating the type (series) of the pin, geometry, material and other information. For example, in the P/N HL18PB-5-16 the HL letters specify a HI-LOK™ fastener, the number 18 determines the geometry and material of the fastener, the letter PB defines the finish protection of the fastener, the -5 number defines the diameter of the fastener per multiples of 32in. ( diameter =5/32 =0,156 in) and the -16 defines the grip length of the fastener per multiples of 16 in. (length = 16/16= 1 in).
HI-SHEAR Fastener Installation/Removal Tools
Different HI-SHEAR Fastener Installation/Removal Tools and Kits and accessories are offered by various manufacturers including HSTOOLING, JIFFY AIR TOOL, USATCO and others and listed in this category. Please refer to the respective product presentations for additional information.
