asme y14.5 2018 standard tolerance section

Depending on the datum references, it can mean something different than a multiple single-segment control.Ĭoncentricity - A geometric tolerance used to control the median points of all diametrically opposed elements of a circular feature, in order to be congruent with a datum axis. It is commonly misused usually runout or position can suffice. The error is sometimes described as TIR.Ĭomposite feature control frame - Sometimes used for profile or position controls, a feature control frame that displays one symbol centered between two or three tolerance specifications.

Therefore, it controls circularity, concentricity, and orientation. On some prints, the basic dimensions are not shown, because they are contained in the “math model,” or the perfect part as defined by the CAD data.īonus tolerance - An additional tolerance beyond what is given in the feature control frame. This is allowed if the tolerance number is followed by the MMC (or LMC) modifier. The amount of bonus tolerance is determined from the difference between a feature’s actual size and the MMC (or LMC).Ĭircularity - A geometric tolerance used to control all points on a surface, at any perpendicular cross-section, to be equidistant from the axis. Sometimes referred to as roundness.Ĭircular runout - A geometric control that limits that amount that a circular cross-seciton can vary as it rotates around a given datum axis (which must be different from its own axis).

It is available in print book or PDF format.īasic dimension - A number, traditionally shown within a box, used to describe the theoretically exact size, angle, location, or profile of a feature. It replaces the previous 2009 edition, and features many changes, although many are minor changes (but notable is the deletion of concentricity and symmetry). A more extensive glossary is distributed to each participant in our seminars.Īngularity - The geometric tolerance used to control a surface, axis, or center plane that is designed to be at a specified angle from a given datum.ĪSME Y14.5-2018 - The current standard for dimensioning and tolerancing in North America. The following is a list of definitions for the most common terms used in GD&T.

Asme y14.5 2018 standard tolerance section