Innovative Fastener Thread Form Can Take the Heat and Vibration of Diesel Engines

         Imagine harnessing the heat energy of a blast furnace while keeping the vibrational equivalent of a jet fighter's acceleration in check. This is essentially what diesel engine engineers worldwide must do to keep diesel trucks on the road and on schedule for thousands of operational hours. Yet for engine performance, reliability, as well as meeting emission standards, joint integrity must be maintained in critical areas such as turbocharger mounts, exhaust manifold joints and attachments, where extreme heat and vibration can weaken and shake loose standard fasteners. Spiralock thread form, however, due to its unique design successfully combats fastener loosening and stripping, is more tolerant of cyclic temperature changes than 60° threads using nylon or adhesives, and allows for both thermal expansion and contraction without slippage. 
         "The Spiralock fasteners stay put under engine vibration, and withstand high temperature," says Sam Sutthiwan, a designer for Peoria, Illinois-based Caterpillar, a technology leader and the world's largest maker of construction and mining equipment, diesel and natural gas engines, and industrial gas turbines. "This improves reliability, upholds our reputation with customers, and lowers the need for service repair."
         Besides Caterpillar, other companies like International Truck and Engine and Mack have turned to Spiralock seeking reliable fastening solutions. Recently Shanghai Diesel Engine, one of the largest engine manufacturers in China, adopted Spiralock thread form to solve problems with the unsatisfactory performance of deformed thread nuts. "The design works like using a wedge to keep a door open," says Jessie Zhang, a Sr. Engineer at Shanghai Diesel Engine. "The thread form offers locking performance and vibration resistance in high temperature. It protects the bolt threads and clamped assembly from damage during assembly or service. In the past few years, we've produced tens of thousands of diesel engines with the Spiralock thread form, with very good results for the Chinese and international markets."

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