Brief Review of the Self-Tightening, Left-Handed Thread
Loosening of bolted joints in rotating machines can adversely affect their performance, cause mechanical damage, and lead to injuries. In this paper, two potential loosening phenomena in rotating applications are discussed. First, ‘precession,’ is governed by thread/nut contact forces, while the second is based on inertial effects of the fastened assembly. These mechanisms are reviewed within the context of historical usage of left-handed fasteners in rotating machines which appears absent in the literature and common machine design texts. Historically, to prevent loosening of wheel nuts, vehicle manufacturers have used right-handed and left-handed threads on different sides of the vehicle, but most modern vehicles have abandoned this custom and only use right-handed, tapered lug nuts on all sides of the vehicle. Other classical machines such as the bicycle continue to use different handed threads on each side while other machines such as, bench grinders, circular saws and brush cutters still use left-handed threads to fasten rotating components. Despite the continued use of left-handed fasteners, the rationale and analysis of left-handed threads to mitigate self-loosening of fasteners in rotating applications is not commonly, if at all, discussed in the literature or design textbooks. Without scientific literature to support these design selections, these implementations may be the result of experimental findings or aged institutional knowledge. Based on a review of rotating applications, historical documents and mechanical design references, a formal study of the paradoxical nature of left-handed threads in various applications is merited.
 Krebs RE, Krebs CA., 2003. “Groundbreaking Scientific Experiments, Inventions, and Discoveries of the Ancient World,” Westport, Conn: Greenwood Press
 Junker, G, 1969, “New Criteria for Self-Loosening of Fasteners Under Vibration,” Transactions of the Society of Automotive Engineers, 78, pp. 314-335.
 Kasei S., 2007, “A Study of Self Loosening of Bolted Joints Due to Repetition of Small Amount of Slippage at Bearing Surface,” Journal of Advanced Mechanical Design, Systems, and Manufacturing, 1(3), pp.358-367.
 Yokoyama et al., 2010, “Analytical Modeling of the Mechanical behavior of Bolted Joint Subjected to Transverse Loading,” Journal of Solid Mechanics and Materials Engineering, 4(9), pp. 1427-1443.
 Pai and Hess, 2002, “Three-Dimensional Finite Element Analysis of Threaded Fastener Loosening due to Dynamic Shear Load,” Engineering Failure Analysis, 9(4), pp. 383-402.
 Pai and Hess, 2002, “Experimental Study of Loosening of Threaded Fasteners Due to Dynamic Shear Loads,” Journal of Sound and Vibration, 253(3), pp. 585-602.
 Tomotsugu S. 1978, “Investigation of Bolt Loosening Mechanisms,” Bulletin of JSME, 21(159), pp.1385-1390.
 Mechanical Engineering Design. Shigley and Mishke. McGraw Hill 7 th ed.
 Juvinall and Marshek, 2003, Fundamentals of Machine Component Design, Wiley
 American Machinist, 1896. Cleveland, Ohio: Penton Publishing. 19(22), pp. 3-535, 536-4.
 Scientific American. United States: Munn & Company, 1896. p. 166 “notes on wagon wheels”
 White, Andrew J., 1965, “Passenger Car Safety Dynamics; an Engineering Pilot Study to Determine Comparative Human Injury Potentials in Vehicle Accidents,” Lee, N.H.: Motor Vehicle Research.
 Fernando, S., 2005, “Mechanisms and Prevention of Vibration Loosening in Bolted Joints,” Australian Journal of Mechanical Engineering, 2(2), pp.73-92.
 Gruben KG, López Ortiz C. 2000, “Characteristics of the Force Applied to a Pedal During Human Pushing Efforts: Emergent Linearity,” Journal of Motor Behavior, 32(2), pp.151-62.
 Gruben KG, Rogers LM, Schmidt MW, Tan L. 2003, “Direction of Foot Force for Pushes Against a Fixed Pedal: Variation with Pedal Position,” Motor Control. 7(4), pp. 362-77.
 Fujioka Y, Sakai T. 2005, “Rotating Loosening Mechanism of a Nut Connecting a Rotary Disk Under Rotating-Bending Force,” Journal of Mechanical Design, 127, pp.1191-1197