Credits and licences

Last updated 2026-10-11

Our own code

The tools and page layouts are written for this site. The pages make no requests to other servers.

The calculators use published standard dimensions and textbook formulas, typed into our own code (no third-party tables or libraries are copied):

Drill sizes: number, letter, fractional and metric drill series (ASME B94.11M sizes).
Thread series and basic thread profile: Unified inch threads (ASME B1.1) and ISO metric threads (ISO 261, ISO 68-1); tap drill and % of thread formulas as published by tap manufacturers.
Pipe threads: NPT sizes and gauge formulas of ASME B1.20.1; tap drill sizes as commonly published by tap makers.
Cutting speed, feed, chip load, chip thinning and material removal rate: standard machining formulas (RPM = cutting speed ÷ π × diameter).
Surface finish: N roughness grades of ISO 1302; theoretical turned roughness and cusp height from tool geometry.
True position: diametral position tolerance as defined in ASME Y14.5.
Gauge block sets: the standard 81-piece inch and 87-piece metric sets.

None at present. If we add any library, font or data set, it will be listed here with its licence and a link (data/credits.json, rendered below).