WCA September 2020

Products

Tangless and tanged CoilThread inserts ❍ (From left) Thin wall insert, CoilThread insert and solid insert. All three samples have the same internal thread, but CoilThread inserts require the smallest boss diameter

their mil-spec qualifications. The inserts have been thoroughly tested by an independent testing laboratory and are certified to conform to NASM8846. When installed into STI tapped holes (per NASM33537 for unified and MA1567 for metric), CoilThread inserts provide a finish thread meeting the requirement of FED-STD-H28. Assembled CoilThread inserts will also accommodate UNJ (MIL-S-7742 and AS8879) male threaded fasteners. The tangless CoilThread inserts are identical, in form, fit and function, to the conventional tanged inserts (CoilThread, Helicoil and Recoil). The only way they differ is in their method of installation and removal. Kato CoilThread inserts are used in aircraft applications such as engines, gearboxes, fuel systems, radar, avionics, flight controls, lighting and HVAC systems. They are also used by the military and in other electronic, mechanical and commercial applications. The tangless, FOD-free design is the preferred standard for optimum thread assemblies in new fastening system designs. Kato Fastening Systems, Inc www.katofastening.com

to support the internal and external threads. For the same nominal thread size, the parent material thickness requirement is less when compared with thin wall or solid inserts. The resilient design characteristics of CoilThread inserts allow each coil to adjust independently for maximum surface contact with the parent material. As a result, loads are distributed more evenly, and stress and fatigue concentrations are reduced to maximise thread strength, increasing the reliability and life of the fastening system. CoilThread inserts are designed to be installed in reduced-sized bosses or flanges, saving space and weight while providing high strength. A boss radius equal to the nominal bolt diameter is usually sufficient. Precision engineering, exacting manu- facturing standards and stringent quality control procedures during the manufacturing process ensure quality that meets or exceeds applicable military and aerospace requirements. Kato CoilThread inserts have undergone rigorous torque, tension and vibration tests as well as comprehensive dimensional inspections and metallurgical analysis in attaining

Kato tangless and tanged CoilThread inserts are helically coiled fastening devices that provide permanent, wear-resistant threads, exceeding the strength of most parent materials. CoilThread inserts are made of cold-rolled 304 stainless steel wire (AS7245), work-hardened to a tensile strength above 200,000 psi and a hardness of Rc 43-50. The finished surface (32 microinches) is very smooth, virtually eliminating friction-induced thread erosion. Tangless and tanged CoilThread inserts are available in Unified Coarse (UNC), Unified Fine (UNF) and metric thread sizes. In addition to 304 stainless steel, the inserts can be manufactured using Nitronic 60 ® , Nimonic 90 ® , phosphor bronze and other materials. The tangless and tanged CoilThread inserts provide design and manu- facturing flexibility, and are based on a continuous helically coiled open pitch design using a diamond-shaped wire. The diamond-shaped wire design allows the inserts to engage the threads in the parent material and at the same time accept a male fastener, so they do not need a thick wall structure

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Fasteners ASIA – September/October 2020