Tag: GD&T
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Socket head cap screws paired with counterbore holes offer flush mounting, clean aesthetics, and protection. Perfect for precision engineering with space constraints.
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This guide explains two approaches to dimensioning holes on a 2D technical drawing: prioritizing hole position for non-critical assemblies, or critical mating components.
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Understanding engineering limits and fits are a staple for every engineer in order to create well functioning mechanical assemblies. In this article we are going to focus on slip fit vs press fit. What are the key differences, the advantages and disadvantages of both and some practical examples.
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Similar to other geometric tolerance group, run-out can be split into two categories, a 2D (circular run-out) and 3D (total run-out) variant. Circular run-out can control the circularity of a feature relative to the components axis bounded by a 2D tolerance zone. This can be considered as measuring a combination of the component’s co-axiality and…
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Total run-out can control the cylindricality of a feature relative to the components axis bounded by a 3D tolerance zone combing the applied control of co-axiality and cylindricality. Unlike circular run-out, total run-out is a measure of the full length of the applied surface as the part is rotated. Controlling other Features with Run-Out Both…
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Datums are the key to good profile tolerances In both cases, profile tolerances only control the form of a feature. To control the feature’s orientation or location, datum features must be called out in the tolerance frame. In the examples below, all four examples would pass inspection! As the designer, you must communicate the right…
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For symmetry control, the tolerance is applied to the theoretically exact centre (axis or plane) of the datum shown in the tolerance frame. Similar to concentricity, the theoretical median plane of the slot must lie within 0.2mm tolerance zone stated, the width of the slot is treated separately. Also shown, the depth of the slot…
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Positional tolerances, in order to determine the location of features, theoretical exact dimensions and a control feature frame can determine the locations of any feature (points, axes, planes and median surfaces). The tolerance zone is located symmetrically about the theoretical centre. For fixing locations, always use positional tolerance.For viewing or access holes, linear dimensions may…
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Concentricity… or Co-axiality Both concentricity and co-axiality share the same control feature symbol which can cause confusion. Concentricity = 2D & Co-axiality = 3D Concentricity is a 2D tolerance zone feature around a theoretically exact centre point of the datum. Typically used to control position of one circle to another, however as form is not…
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In this example we have used flatness to control our surface datum ‘A’. The upper surface is defined to be parallel to surface datum ‘A’ as shown in the control frame, to the value specified. Parallelism can also be used to control the relationship between hole centres. Note the use of the diameter symbol in…