McGuire Glossary of Fastener Terminology

J - 9 terms

JACK-OUT - A testing method that applies torque to a fastener to pull it out of a panel.

JAPANNING - A type of finish that originated as a European imitation of Asian lacquerwork. It was first used on furniture, but was later much used on small items in metal and is most often a heavy black "lacquer". almost like enamel paint.

JIDOKA - A form of automatic inspection of each item produced. Production is halted and workers are notified if a defect is detected.

JIG - In manual machining, a jig used to hold the workpiece and also to guide the tool.

JIS - Japanese Industrial Institute. It specifies the standards used for industrial activities in Japan.

JIS B 1012 - This drive recess is commonly found in Japanese made equipment. Superficially it looks like a Phillips screw with narrower and more vertical slots, to give less tendency to cam out. The bottom of the recess is flat, and the point of the driver has to b blunt. A Phillips driver will not seat fully and will damage the screw if forced. The driver is available in three sizes.

JOINT MATERIAL - The application material which is being fastened together. Also referred to as the parent material.

JOST EFFECT - The name given to the reduction in the frictional resistance that occurs in a direction different to that inwhich slip is occurring. This effect is used in many applications including the removal of corks from bottles. It the cork is first rotated the force needed to pull the cork from the bottle is significantly reduced. It is also the fundamental reason why threaded fasteners experience self-loosening. Frictional resistance is first overcome in the transverse direction by slip occurring in the joint resulting in the frictional resistance in the circumferential direction reducing to a small value. The torque acting on the fastener is in the loosening direction (as a result of its prelaod) that when coupled with the Jost Effect results in self loosening occurring.

JUST IN TIME (JIT) - A production scheduling concept that calls for any items needed at a production operation (whether raw material or finished items) to be produced precisely when needed (not earlier or later).