2024 ARP Catalog

15 There are no back up provisions for component failure. A failed (or even loosened) nut or bolt in a racing engine means disaster – instant catastrophic failure. An expensive engine is destroyed and a race is lost. That is why random failures are unacceptable in motor racing, and why aerospace standards should be only a starting point. This means that a specialist in the production of high performance engine fasteners must design and manufacture the very best fasteners that can be produced.” Smith: “So where does the production for a new racing fastener begin?” “The design process begins with the customer’s requirements the operating conditions and loads to be expected, the packaging constraints and the weight and cost targets. This allows us to select the optimummaterial for the part, and to do the initial mechanical design. There is more to material selection than simply choosing the best alloy. It means using only the cleanest and purest steel available, which, in turn, means researching to identify the best and most modern steel mills. It means working closely with the mills both to insure consistent quality and to develop new and better alloys. There are not only a myriad of alloys to choose from; but for each alloy there are several grades of “aircraft specification” steel wire from which fasteners can be made. We believe that only the top (and most expensive) grade – shaved-seamless, guaranteed defect-free – is suitable for racing engine applications. We also believe that samples fromeach batch should be subjected to complete metallurgical inspection.” Smith: “How many alloys do you work with?” “We are currently producing fasteners from at least 10 different steel alloys from 8740 chrome moly to the very high strength chromium-cobalt-nickel alloys such as Custom Age 625+. We also use stainless steel and titanium. With UTSs (Ultimate Tensile Strength) from 180,000 to 270,000 psi, we can suit the material to the job and the customer’s cost restraints. We are continually researching and experimenting with new alloys and manufacturing processes – some with all around better strength and fatigue properties.” Smith: “Once the design work is done and material has been selected, what’s next?” “Next comes the actual process of manufacturing. It goes without saying that all high strength bolts must have rolled rather than cut threads, and that the threads must be rolled after heat-treatment. But there is more to it. The old saying to the effect of, “If you are doing something in a particular way because that’s the way it has always been done, the chances are that you are doing it wrong,” holds true in fastener technology. Technology advances, and we have to advance with it. All of the manufacturing processes should be subject to continuous experimentation and development. As an example, with some alloys, cold This spring was wound from un-shaved material. It failed on the seam line. 5 stage “Cold Header” used in the production of ARP bolts FASTENER TECH