Expandable dowel fasteners are special bolts used to expand in a hole to prevent fretting and/or to fit components. These fasteners can eliminate the need of expensive close tolerance machining or press fits.
When a compressive force is applied to the ends of the bushing stack, the diameter of the fastener increases. When the force is relaxed, the bushings return to their original diameter, and the fastener can easily be removed and reused.
The LISI AEROSPACE family of expandable diameter fastening solutions can be found in multiple configurations to fit customers' assembly alignments. We provide a bolt and standard nut tooling solution as well as a blind expandable bolt to align structures prior to their final assembly. They can be used as shafts in their airborne versions and cam-operated when expansion requires high torque capabilities. Thanks to our dedicated R&D department, LISI AEROSPACE regularly proposes customized solutions to our clients.
Our products satisfy both tooling and airborne applications, they can be used to pre-align assemblies for aircraft engine mounting, helicopter blade attachment or mounting of anti-friction bearings and they can also be beneficial when design requires a tighter joint (for example, transmission in primary and secondary flight controls).
Benefits: no radial clearance, rigid joint, holes alignment, repeatability, reusability, vibration reduction, easy and quick release fastening. For many years LISI AEROSPACE has developed expandable dowels, from diameter .1900 to 1.5000 inches. Metric sizes also available on request. Special options can be provided: captive segments, lanyard, impedance ring, dual locking feature.