{"id":20971,"date":"2025-08-15T00:27:32","date_gmt":"2025-08-15T08:27:32","guid":{"rendered":"https:\/\/shengenfab.com\/?p=20971"},"modified":"2025-08-15T00:51:39","modified_gmt":"2025-08-15T08:51:39","slug":"true-position-in-gdt","status":"publish","type":"post","link":"https:\/\/shengenfab.com\/en_gb\/true-position-in-gdt\/","title":{"rendered":"True Position in GD&T: What It Means and Why It Matters\uff1f"},"content":{"rendered":"
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True Position is one of the most widely used concepts in Geometric Dimensioning and Tolerancing (GD&T). It offers a more complete way to define the location of features on a part, especially holes and slots. Instead of standard X and Y dimensions with individual tolerances, True Position controls the overall deviation from a perfect location using a circular or cylindrical tolerance zone.<\/p>

By using True Position, engineers can control how much a feature can shift in any direction from its ideal location. This approach is much more effective than separating \u00b1 tolerances for each coordinate. It also works better for features aligning with mating parts or assemblies. Let’s break it down from the start.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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What Is the True Position in GD&T?<\/h2>

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True Position is the exact location of a feature, such as a hole, pin, or slot, as defined concerning datums. Simply, it tells us where a feature should be placed on a part. Instead of focusing on the exact X and Y values, it defines a zone\u2014usually a circle or cylinder\u2014within which the center of the feature must fall.<\/p>

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This zone is centered on the theoretical location, called the “nominal” location. The part is considered acceptable if the actual center of the feature falls within the zone. The size of the zone depends on the allowed tolerance, which is specified in the feature control frame.<\/p>

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For example, if a hole’s true position tolerance is 0.2 mm, the center of that hole must fall within a 0.2 mm diameter circle around the exact target location. Whether the hole shifts left, right, up, or down, it’s still okay if it stays inside that circular area.<\/p>

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True Position is often used with other GD&T symbols, such as datums, material condition modifiers like MMC (Maximum Material Condition), and basic dimensions. These elements work together to describe a feature’s location, size, and limits more clearly than traditional tolerancing.<\/p>

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Key Symbols and Terminology<\/h3>

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To work with True Position, it’s important to understand the key symbols and terms used in a GD&T feature control frame. These elements define how the tolerance is applied and what measurements matter.<\/p>

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