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- P -
Paddle Method (preload test) -
A method for determining fastener preload, or, more specifically, the load required to "undamp" a fastened fixture assembly and permit movement of the paddle.
Pan Head -
A protruding head with a flat top which rounds to a cylindrical outside diameter.
Panel (access) -
A panel so attached as to facilitate removal and replacement for interior inspection or repair purposes.
To change the chemically active surface (normally by the removal of free iron) of a material to a much less reactive state and thus inhibit corrosion.
Permeability (magnetic) -
A general term used to express various relationships between magnetic induction and magnetizing force.
An optical method for evaluating the magnitude and distribution of stresses in a given transparent or transparent film coated specimen. Variations of load will then produce variable and visible stress distribution patterns through light refraction; viewed and evaluated using polarized light.
Physical Properties -
Metallurgically, the properties, other than mechanical properties, that pertain to the physics of a material such as density, electrical conductivity, heat conductivity, thermal expansion, etc.
Removing surface oxides from metals by chemical or electrochemical reaction.
A cylindrical or tapered fastening device, with or without head or threads, designed to hold parts together.Some special types are as follows:
Ina rivet, blind fastener, or lockbolt, an extension of the fastener which mates with a tool for pulling to effect fastener installation. The pintail breaks off after completed installation.
Metallurgically, an extrusion defect due to the oxidized surface of the billet flowing toward the center during the forming of rod, bar or wire.
The distance between corresponding points on adjacent identical features of a repetitive design or pattern.
Pitch Diameter -
In straight thread geometry, the pitch diameter is the diameter of a theoretical cylinder which intersects the thread profiles at the points where the widths of the thread and groove are equal.
Infastener configuration, the chamfered thread end of bolts which facilitates engagement with mating threads.
Poisson's Ratio -
The absolute value of the ratio of the transverse strain to the corresponding axial strain in a body subjected to uniaxial stress; usually applied to elastic conditions.
Usually a catalyzed adhesive compound, chemically or thermally activated to solidify and bond a fastener to core material and skin of sandwich panels and provide retention of the device.
Powder Metallurgy -
The art of compacting metal powders for the production of metallic components.
Precipitation Hardening -
See Heat Treatment
Clamping workpieces together during hole preparation and/or prior to and during installation of fastening devices.
The amount of residual axial clamping load remaining in the fastener system after complete installation in a workpiece.
A machine having a stationary bed and a slide or ram which has reciprocating motion at right angles to the bed surface to apply compressive loading.
Process Annealing -
See Heat Treatment
Proof Load -
A predetermined load, generally some multiple of the service load, to which a component or structure is subjected before acceptance for use.
Proportional Limit -
The maximum stress at which strain remains directly proportional to stress.
Pull Grooves -
Serrations or features formed in a pull stem to improve gripping capability of jaws (collet) of a pull tool when applying an axial load to a fastener during installation.
Pull Stem -
An extension of a fastener which engages a tool capable of exerting an axial pulling force to install the fastener. The pull stem separates at a predetermined force.
Pull Tool -
A tool that exerts an axial force on a fastener extension, (i.e., a pull stem) in installation. Loads applied are normally reacted into swaging or deforming a fastener component.
Push Out -
A test criterion applying to the resistance of a fastener to displacement when a specified axial load is exerted in the direction opposite normal loading.