Position at RFS: turning coordinate deviations into a position value

How true position is computed from X and Y deviations, why the answer is a diameter, and what regardless of feature size actually means on the shop floor.

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Position at MMC and bonus tolerance, explained with the arithmetic

What the maximum material condition modifier grants, how the bonus is computed for holes and pins, and why the allowance is bounded by the size tolerance.

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Least material condition: protecting wall thickness rather than assembly

When to reach for the LMC modifier, how its departures reverse every direction learned at MMC, and why it is harder to gauge.

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Virtual condition and resultant condition, and when neither exists

How to compute the constant worst case boundary in all four directions, what the resultant condition adds, and why there is no virtual condition under RFS.

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Datum shift: why it is not extra tolerance on the feature

Where datum shift comes from, how much of it a datum feature of size permits, and why adding it to the acceptance limit accepts parts a gauge would reject.

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Reading a feature control frame compartment by compartment

The order of the compartments, where the material condition modifier belongs, why RFS is never written, and what the extent indicators add.

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Datums, precedence, and counting degrees of freedom

The difference between a datum feature, a datum, and a simulator, how precedence works, and how many degrees of freedom each kind of datum feature constrains.

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Size limits and Rule #1, the envelope requirement

What a size dimension controls on its own, how the envelope requirement limits form, and when independency removes it.

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Profile of a surface and of a line, and what one frame can control

How a profile zone is disposed about true profile, the difference between the surface and line characteristics, and why profile can replace size, form, orientation and location at once.

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Runout: reading an indicator against a rotating part

Full indicator movement, the difference between circular and total runout, and why a runout number is a good requirement and a poor diagnostic.

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Orientation: perpendicularity, parallelism and angularity

What an orientation tolerance controls and what it deliberately leaves alone, how it refines a position tolerance, and how it limits form as a side effect.

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Form controls: flatness, straightness, circularity, cylindricity

Why form controls take no datum, what each zone looks like, how much form the size tolerance already implies, and when an explicit callout earns its place.

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Composite position: locating a pattern and relating its features

How the two tiers of a composite frame differ, why the lower tier repeats only some datums, and what changes if the frame is split into two.

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From a drawing requirement to a measurement that answers it

Sizing a functional gauge, why MMC can be gauged and RFS cannot, what a report has to carry, and the conditions measurements are defined at.

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Where to go next