In engineering and drafting, a datum is a reference point, surface, or axis on an object against which measurements are made. These are then referred to by one or more 'datum references' which …

Datums are theoretically exact points, axes, lines, and planes or a combination thereof that are derived from datum features. A datum feature is the tangible surface or feature of size (comprised of multiple …

Jan 2, 2025 · Datums are basically the starting point of any measurement—they keep measurements accurate throughout the manufacturing, the assembly, and the quality checks. 1. Primary Datums. …

A datum feature can be a plane, line, or point, which needs to be used selectively depending on the tolerance and feature you need to specify. This page explains the indication symbols and how to …

Jul 26, 2025 · So, what exactly is a datum? A datum is a reference line, plane or point. Users refer to this point for subsequent measurements. Consider a metal that should have a hole drilled on one face.

In GD&T, a datum refers to a reference point, line, or surface that serves as the origin for measuring and locating other features of a part. As such, it plays a critical role in ensuring precise alignment, …

Apr 30, 2025 · A datum is a theoretical reference point, line, or plane used to establish a coordinate system for measurement and design. Think of it as a zero point or starting location that engineers …

Mar 28, 2022 · The Datum Target Symbol is used to define a specific point, line, or area to be used in order to establish a datum on a drawing.

Apr 11, 2023 · ASME Y14.5 (1994) defines a datum as “A theoretically exact point, axis, or plane derived from the true geometric counterpart of a specified datum feature. A datum is an origin from …

Jul 11, 2025 · In GD&T, a datum is a theoretically perfect point, axis, or plane that serves as a reference for measuring and manufacturing parts. While actual part features may have imperfections, datums …