DICTIONARY

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Reamer -
A cutting tool utilized in hole sizing to produce close tolerance dimensions. The reamer removes small amounts of material at slow rates in a previously rough drilled hole, producing a smooth, blemish-free surface.
Recess -
A feature formed into a fastener to provide an internal wrenching means. Following are examples:
Recrystallization -
A change from one crystal structure to another upon heating or cooling through a critical temperature. Formation of a new, strain-free grain structure from the structure of a cold-worked metal, usually accomplished by heating.
Reduction of Area -
The difference, expressed as a percentage of original area, between the original cross-sectional area of a tensile test specimen and the minimum cross-sectional area measured after fracture of the specimen. Reduction of area data is used as a rela...
Refractory Materials -
Utilized in extremely high temperature applications above the melting point of common metals. Characteristics include minimal heat absorption, transmission, and reaction.
Relaxation -
Relief of stress by creep. The effect of relaxation is to reduce the preload in a fastened joint until a state of equilibrium is reached.
Relief -
In fasteners, a groove or undercut to provide additional clearance. Usually used to remove transition material.
Residual Pre stress -
See Preload
Residual Stress -
Stress present in a material which is free of external forces or thermal gradients. Usually, the result of heat treating, forming, grinding, or other machining.
Retainer Ring -
A removable ring utilized as a shoulder to prevent the disengagement of assembled components.
Rivbolt Rivets -
A uniquely configured, high strength rivet producing more uniform radial expansion in hard workpieces.
RivboltĀ® -
A unique fastening system consisting of a rivet, a collar and special tooling used to produce controlled interference-fit in a workpiece, to increase joint fatigue life.
Rivet -
As a general term, a rivet is a non-threaded fastener system which is formed in the structure.
Rivet (solid) -
A headed, straight or tapered shank made of ductile material. The fastener is upset by application of axial load. Upset of the shank produces radial expansion in the hole in the workpiece and forms a head on the end of the fastener opposite the manufactured head.
Rivet Hammer -
A device capable of delivering multiple blows to a rivet to produce compressive yielding and shank upset. Load is reacted by a bucking bar at the opposite end of the fastener. The device may also be used with unique terminal tools to swage collars.
Rivet, Blind -
A multi-piece rivet assembly, capable of being installed from one side of the workpiece. Minimum components are a sleeve with a head and a center stem or spindle. Installation forces, acting through the spindle head and reacted against the sleeve head, cause the sleeve to deform on the back side to provide bearing to clamp and join workpieces.
Rivetless Plate Nut -
A nut assembly installed in a workpiece by insertion from the back of the work in a prepared hole. A protruding pull stem mandrel is engaged at the front of the work by an axial pulling tool which pulls the expanding mandrel through a barrel element ...
Rockwell Hardness -
See Hardness
Roll Threading -
A method of producing helical or annular depressions in cylindrical surfaces by displacement and compaction of material, as opposed to cutting and removal.
Root (thread) -
The transitional surface or valley between adjacent thread forms.
Running Torque -


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