Industrial Manufacturing News

Because lighter, stronger, higher speed, RPM and temperature designs are required for today's most demanding applications, engineers are turning to Spiralock self locking threaded fasteners over traditional secondary thread locking devices such as lock washers, adhesives, or prevailing torque fasteners, which may add weight, cost and complexity over the product life cycle.

Notes for achieving best results are given. On drill sizes for cut tapping, for instance, a hole minor diameter on the low side of the suggested range is recommended for soft metals such as aluminum. For harder materials, a hole minor diameter on the high side of the suggested range is recommended.

For hole sizes for cold form tapping, best practice advice is also given. For example, to get good results, you must know the actual hole size and not just the drill size. What matters is the actual pretap hole size, how consistently this hole size is maintained, and the after-tap thread percentage or minor diameter.

A few cautions on cold form tapping are also given. For instance, thin wall parts may expand during tapping and produce oversize after-tap minor diameters.

What makes Spiralock self-locking fasteners unique is the 30-degree wedge ramp at the root of the thread which mates with standard 60-degree male thread fasteners. The wedge ramp allows the bolt to spin freely relative to female threads until clamp load is applied. The crests of the standard male thread form are then drawn tightly against the wedge ramp, eliminating radial clearances and creating a continuous spiral line contact along the entire length of the thread engagement. This continuous line contact spreads the clamp force more evenly over all engaged threads, improving resistance to vibrational loosening, axial-torsional loading, joint fatigue, and temperature extremes.

The innovative self locking threaded fasteners thus compensate for variations in manufacturing tolerance and process due to mass production with its locking thread actually inside the joint. This eliminates the need for secondary thread locking devices or procedures, and can significantly reduce costly warranty claims and potential liability. The self locking fasteners have been used in thousands of manufacturing applications to solve design challenges in a wide range of industries.

Production changeovers to these self locking threaded fasteners are typically quick and seamless, often requiring just an exchange of traditional nuts, wire inserts or simply drilling out and re-tapping existing parts stock that have unreliable standard tapped holes.

Spiralock
Kate Turowska
Madison Tech Center
PO Box 71629
Madison Heights, MI 48071
KTurowska @ spiralock.com
www.spiralock.com
Phone (800) 521-2688