Toolmaker Teacher

American National Standards Institute(ANSI)
A set of drafting standards which are recommended for drawing practice.
Datum
A point, line, plane, or other geometric surface from which dimentions are measured when so specified or to which geometric tolerances are referenced.
Datum Feature
A feature of a part, such as the edge or a surface, which forms the basis for a datum or is used to establish its location.
Dimention
A geometric characteristic, of which the size is specified, such as diameter, length, angle, location, or center distance.
Feature Control Frame
A box found on engineering drawings, that is divided into compartments containing the geometric characteristic symbol followed by the tolerance.
Geometric Tolerance
The maximum permissible variation of form, profile, orientation, location, and runout from that indicated or specified on the drawing.
Least Material Condition (LMC)
Refers to the size of a feature which results in the part containing the minimum amount of material.
Maximum Material Condition (MMC)
When a feature or part is at the limit of size which results in it containing the maximum amount of material.
Tolerance Value
This represents the width or diameter of the tolerance zone, within which the point, line, or surface of the feature shall lie.
Virtual Condition
Refers to the overall envelope of perfect form within which the feature would just fit.