Abstract: Helical groove fasteners and methods for producing the same are provided for use in systems requiring fluid passage through the fastener. In one embodiment, the fastener includes a shank, a head, a threaded portion, and at least one groove extending through at least a portion of the threaded portion. The fastener can include a single groove or multiple grooves. In certain preferred embodiments, the helix rotation angle of the groove is selected so that the shank has a continuous diameter to facilitate the thread forming process. In preferred embodiments, the fastener is cold forged and the threads are formed using a thread rolling die.

Abstract: A method of fastener identification for traceability of manufacturing information of an individual fastener, is achieved by applying a code to the fastener. The fasteners to be identified typically are formed of hardened materials such as steel. A die cast, forged or pressed roll stamp or forge stamp is thus used to apply the code and is formed with a raised stencil of one or more characters or indicia. Multiple lots of a certain fastener typically are manufactured in a given time period, such as a year, thus requiring a different code to identify each fastener lot. Numbers of lots and sizes of individual lots for a given time period are difficult to predict for a fastener producer, thus risking waste if multiple customized stamps are used to identify the lots. A universal stamp having a single indicia stencil is utilized to identify all lots of a certain fastener in a given time period, by removing selected ones of the stencil characters from the universal stamp for each different lot.

Abstract: A method of measuring the load in a member subjected to longitudinal stress, a load measuring device and a fastener tightening device using the method of measuring, a load indicating member and a load indicating fastener for use in conjunction with the method of measuring, a method of making the load indicating fastener, and a method of tightening the load indicating fastener. A preselected end of a pin is secured to a shank of a load indicating member, such as a load indicating fastener, in a manner such that the pin is unaffected by the elastic deformation of the shank in response to longitudinal stress. Coplanar first and second flat surfaces are formed, respectively, adjacent to the longitudinal ends of the pin and the shank furthest from the preselected end of the pin such as to provide reference surfaces for the measurement of the elongation of the shank in response to longitudinal stress.

Abstract: A method of measuring the load in a member subjected to longitudinal stress, a load measuring device and a fastener tightening device using the method of measuring, a load indicating member and a load indicating fastener for use in conjunction with the method of measuring, a method of making the load indicating fastener, and a method of tightening the load indicating fastener. A preselected end of a pin is secured to a shank of a load indicating member, such as a load indicating fastener, in a manner such that the pin is unaffected by the elastic deformation of the shank in response to longitudinal stress. Coplanar first and second flat surfaces are formed, respectively, adjacent to the longitudinal ends of the pin and the shank furthest from the preselected end of the pin such as to provide reference surfaces for the measurement of the elongation of the shank in response to longitudinal stress.

Abstract: A blind fastener assembly is disclosed, which is suitable for use in joint assemblies including advanced composite materials. The fastener assembly includes a pin, an expander, a sleeve, and an expandable washer, each of which have an initial diameter which permit them to pass through a hole in the workpiece. The washer is mounted about the pin shank between the sleeve and a tapered nose portion of the expander. The fastener assembly is inserted in a hole in the workpiece so that the expander head abuts the workpiece. Rotation of the pin causes the sleeve to force the washer to slide over the tapered nose portion of the expander causing it to expand and abut the blind side of the workpiece. In one embodiment of the invention the pin threadably engages the expander, and the head of the pin is positioned on the blind side of the workpiece. The washer is initially seated in a groove in the pin shank.

Abstract: Apparatus and method for determining dynamic friction in a threaded joint and an associated tightening system for tightening such joints including threaded fasteners. A value representative of the coefficient of friction in the threaded joint is obtained by determining the gradient of a torque-rotation curve which could be plotted for the joint being tightened, and dividing this gradient by the product of the fastener pitch diameter and the tension rate of the joint. The desired tightened condition is achieved by computing the tightening torque required to induce a predetermined preload in the threaded fastener and comparing this computed torque with the instantaneous torque being imparted to the fastener. When the two torques are equal, tightening of the fastener is stopped.