Chapter A: A Axis of Thread

A-

A

(1) Symbol for ampere; (2) an unofficial symbol for the element argon; (3) symbol for acceleration; (4) symbol for amplitude; (5) symbol for atomic weight; (6) symbol for area.

See also alpha (A or ?).

Symbol for angstrom unit.

A

A, ?

See also alpha (A or ?).

A ₁

The eutectoid temperature of steel.

AA

(1) Abbreviation for arithmetical average; (2) Abbreviation for Aluminum Association.

AAI

Abbreviation for Aluminum Association, Inc.

AAR

Abbreviation for Association of American Railroads.

ABMA

Abbreviation for American Bearing Manufacturers Association.

ABFMA

Abbreviation for Anti-Friction Bearing Manufacturers Association.

abherent

Any substance that prevents adhesion of a material to itself or to another material, such as mold release agents.

abrasion

The process of wearing away material by mechanical action, friction, shearing; or, using abrasive materials in actions such as erosion, grinding, honing, lapping, rubbing, superfinishing, or polishing.

abrasion resistance

The ability of a material to resist wear by friction or shearing action.

abrasive

A manufactured or natural very hard, tough material capable of wearing away another material softer than itself. Used for grinding and improving a surface by friction, as in polishing, buffing, cleaning. Emery (alumina), pumice, silica (sand), rouge (iron oxide), and diamond dust are examples of natural abrasives. Aluminum oxide [Al ₂O ₃], silicon carbide [SiC], cerium oxide, fused alumina, and boron carbide [B ₄C] are examples of artificial abrasives. Sandpaper, steel shot, glass beads, and steel wool are also examples of...