Sources & Licences

ISO 286 Fits: engineering basis ISO 286-1/286-2. Numerical implementation is re-provenanced against Parker Greene’s isofits 1.0 (MIT), with ShopMath’s independently cross-checked ISO 286 dataset used as validation. Release scope: 3–400 mm; s/t/u zones excluded.

GD&T Reference. Original Machinist Companion explanations, diagrams, and first-principles calculations are validated primarily against public NIST GD&T educational publications and ASME public Y14.5 scope/overview material. The copyrighted ASME Y14.5 standard itself is not embedded, reproduced, or used as an app data table.

NBS Handbook H28 — Screw-Thread Standards for Federal Services. U.S. National Bureau of Standards. Primary public technical basis for Unified screw-thread geometry, Unified tap-drill guidance, pipe-thread reference work, and the three-wire measurement method where applicable.

ISO 965 metric thread tolerance system. Engineering basis for external metric 6g/6h pitch-diameter limits used by Three-Wire. Current ISO 965-6 covers both 6g and 6h. The app retains published whole-micrometre product-limit values and validates representative sizes against independent thread/gage references.

ThreadBuddy. MIT-licensed clean-room thread calculator. Used as an independent implementation/validation source for inch and metric thread calculations. Its ISO 965 position allowance is useful as a cross-check, but its documented lack of tolerance-band modelling means it is not used as the source of the 6g/6h band width.

tq-threads. MIT-licensed clean-room implementation. Approved candidate for exact listed metric pitch presets, ISO 273 clearance-hole values, ISO 4762 socket-head fastener envelope data, and ISO 10642 countersunk-head envelope data. Approximate/fallback and FDM-specific values are excluded.

bd_warehouse. Apache License 2.0. Approved candidate for drill-size, clearance-hole, tap-hole, and fastener datasets after file-level provenance and numerical cross-checking. Required Apache attribution/notice terms will be retained if data is incorporated.

Basic geometry calculators, fractional drill dimensions, RPM/SFM/feed conversions, and other first-principles calculations are generated by Machinist Companion rather than copied from tabular publications.

Release status: the numerical datasets intentionally exposed by the production application are limited to scopes that passed the project’s provenance review. Sources are app-authored, public/government, independently compiled factual data, or open-source/permissively reusable material with required notices retained.

Controlled scope: where a source or engineering method supports only part of a standard or size range, Machinist Companion limits the tool to that supported scope rather than silently extrapolating unsupported values.

Standards references: copyrighted standards may be cited as engineering authority or validation context without embedding or redistributing the standards themselves.

Engineering accuracy: licensing clearance and engineering validation are separate checks. A reusable source is not automatically treated as authoritative, and calculated or converted values remain subject to the limitations shown in the relevant tool.