# Specifications

Datum reference frames, position and form tolerances, surface roughness and thread designations.

[Manufacturing Wiki](https://planar.so/wiki/index.md)

- [Angularity](https://planar.so/wiki/parts-and-design/specifications/angularity.md): Angularity tolerance zones, datum-dependent interpretation and inspection planning, with bounded geometric examples.
- [BSPP threads](https://planar.so/wiki/parts-and-design/specifications/bspp-threads.md): Identifying parallel pipe threads and specifying the separate sealing interface needed for a complete connection.
- [BSPT threads](https://planar.so/wiki/parts-and-design/specifications/bspt-threads.md): Identifying ISO 7 sealing pipe threads, including tapered R/Rc and parallel Rp forms, without confusing fit with qualified joint performance.
- [Circular runout](https://planar.so/wiki/parts-and-design/specifications/circular-runout.md): Interpreting datum-related rotational variation at individual circular elements and distinguishing it from roundness and total runout.
- [Circularity](https://planar.so/wiki/parts-and-design/specifications/circularity.md): Datum-independent roundness, tolerance-zone interpretation and the effects of association, sampling and filtering on inspection.
- [Cylindricity](https://planar.so/wiki/parts-and-design/specifications/cylindricity.md): Interpreting the full cylindrical form zone and planning measurements that reveal variation around and along a surface.
- [Datum reference frames](https://planar.so/wiki/parts-and-design/specifications/datum-reference-frames.md): Establishing repeatable geometric references from specified part features, precedence and constraint rules.
- [Flatness](https://planar.so/wiki/parts-and-design/specifications/flatness.md): Interpreting planar flatness requirements and evaluating them without confusing datum orientation, sampled form, or restraint.
- [ISO metric threads](https://planar.so/wiki/parts-and-design/specifications/iso-metric-threads.md): Metric fastening-thread designations, pitch and tolerance classes, coating state and dimensional versus joint-performance requirements.
- [Least material condition](https://planar.so/wiki/parts-and-design/specifications/least-material-condition.md): Understanding least-material size, geometric tolerance growth and minimum-wall intent without confusing feature and datum modifiers.
- [Maximum material condition](https://planar.so/wiki/parts-and-design/specifications/maximum-material-condition.md): Linking feature size and geometric tolerance for assembly, with explicit envelope, virtual-condition and datum boundaries.
- [NPT threads](https://planar.so/wiki/parts-and-design/specifications/npt-threads.md): NPT identification, taper and gauging, distinctions from NPTF and BSPT, and product-specific sealing and assembly requirements.
- [Parallelism](https://planar.so/wiki/parts-and-design/specifications/parallelism.md): Datum-based orientation tolerances for surfaces, axes, and median features, with practical interpretation and inspection limits.
- [Perpendicularity](https://planar.so/wiki/parts-and-design/specifications/perpendicularity.md): Interpreting datum-related 90-degree orientation zones and measuring the required surface or derived feature.
- [Position tolerance](https://planar.so/wiki/parts-and-design/specifications/position-tolerance.md): Interpreting location zones, datum constraints and material modifiers without reducing every position requirement to a two-coordinate formula.
- [Profile of a line](https://planar.so/wiki/parts-and-design/specifications/profile-of-a-line.md): Interpreting sectional profile zones, datum constraints, tolerance distribution, and measurement coverage without substituting whole-surface or best-fit results.
- [Profile of a surface](https://planar.so/wiki/parts-and-design/specifications/profile-of-a-surface.md): Theoretical surface definition, zone distribution, datum constraints and inspection choices for surface-profile tolerances.
- [Straightness](https://planar.so/wiki/parts-and-design/specifications/straightness.md): Distinguishing surface-line and derived-median-line straightness, with explicit extent, sampling and evaluation choices.
- [Surface roughness Ra](https://planar.so/wiki/parts-and-design/specifications/surface-roughness-ra.md): Arithmetic mean profile roughness, measurement scale and units, standards generations, and comparisons with Rq, Rz and Sa.
- [Surface roughness Rz](https://planar.so/wiki/parts-and-design/specifications/surface-roughness-rz.md): Interpreting profile peak-to-valley roughness with explicit ISO or legacy definitions, filtering and measurement conditions.
- [Total runout](https://planar.so/wiki/parts-and-design/specifications/total-runout.md): Whole-feature runout relative to a datum axis, including radial and face applications, inspection setup, and limits of sectional measurements.
- [Unified inch threads](https://planar.so/wiki/parts-and-design/specifications/unified-inch-threads.md): Unified thread series, TPI and A/B classes, with coating, gauging and joint-performance boundaries.