Gear racks ISO 53 module 1 to 3: tooth profile, pitch, depth and root radius + module 1.5, 2.5, 3 rack STEP/STL — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/gear-racks-iso-53-module-1-to-3/ (sheet CC BY 4.0) Basis: ISO 53 standard basic rack tooth profile (ISO 53:1974 sample pages, 1998 catalogue entry), Sorotec module 1.5 / 2 racks; tooth numbers computed from m; KHK linked for CAD Catalog version: 2026-10-20 Sizes: see table below - The standard basic rack tooth profile (ISO 53; the 1974 edition and the 1998 catalogue entry were read) has a 20° pressure angle, the tips at one module above the reference (pitch) line, a whole tooth height of 2.25 m and a root radius of 0.38 m (up to 0.45 m when meshing needs it); the tooth thickness measured on the reference line equals the space width, so π m / 2. The root depth 1.25 m is the whole depth minus the module (derived, not printed). Every rack with this profile meshes with a spur gear of the same module and 20° pressure angle, whatever its length. - A rack of module m moves π m mm per pinion tooth: one turn of a 20-tooth pinion of module 2.5 moves it 157.1 mm. The pinion's pitch circle runs on the rack's pitch line, so the pinion centre sits at its pitch radius m N / 2 from the pitch line. Sorotec's module 1.5 and 2.0 racks (S45C, HRC 50 to 55, 20°) and KHK's steel racks use this basic profile; their lengths and cross-sections vary by maker and are not in the tables. - Files: three racks (module 1.5, 2.5 and 3), 20 teeth each, with the exact ISO 53 tooth form including the 0.38 m root fillets. Bar width (6 m), body depth under the root (the pitch line is 3.25 m above the back face) and the count of 20 teeth are examples chosen here, not published values; there are no mounting holes (hole patterns are the maker's). Modules 1 and 2 racks are on the existing gear-racks page. Tooth tips are sharp (ISO 53 gives no tip radius); real racks have a small tip relief. - Left out: tooth tolerances, accuracy grades, helical racks (the helix angle is the maker's), and module 4 and above. Module 1.25 is in the table but has no file. module m, mm tooth pitch p = π m, mm tip height above pitch line (m), mm root depth below pitch line (1.25 m), mm whole depth (2.25 m), mm tooth thickness = space width on the pitch line (π m / 2), mm root radius 0.38 m, mm travel per turn of a 20-tooth pinion (π m 20), mm pitch per tooth, mm 1 3.142 1 1.250 2.250 1.571 0.380 62.83 3.142 1.25 3.927 1.25 1.562 2.812 1.963 0.475 78.54 3.927 1.5 4.712 1.5 1.875 3.375 2.356 0.570 94.25 4.712 2 6.283 2 2.500 4.500 3.142 0.760 125.66 6.283 2.5 7.854 2.5 3.125 5.625 3.927 0.950 157.08 7.854 3 9.425 3 3.750 6.750 4.712 1.140 188.50 9.425 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - ISO (iTeh sample pages): ISO 53:1974 Cylindrical gears for general and heavy engineering, standard basic rack tooth profile: 20°, tips at m, tooth height 2.25 m, root radius 0.38 m, tooth thickness = space width — web — Publisher's page; dimensions are facts — https://cdn.standards.iteh.ai/samples/3690/215220a7b6fe436c803d65d8ae04eb41/ISO-53-1974.pdf - ISO: ISO 53:1998 Standard basic rack tooth profile (catalogue entry) — web — Publisher's page; dimensions are facts — https://standards.iteh.ai/catalog/standards/iso/032d8eaa-c5ba-4f3c-96d6-592df1cd067d/iso-53-1998 - Sorotec: Racks and pinions datasheet: module 1.5 and 2.0 racks, 20° pressure angle, S45C — web — Publisher's page; dimensions are facts — https://www.upload.sorotec.de/doku/manuals/Datasheet_Racks-and-Pinions_EN-DE_soro.pdf - KHK Gears: Steel racks with machined ends (SRAF / SRAFD / SRAFK): the maker's CAD and catalogue page — web — Publisher's page; dimensions are facts — https://khkgears.us/catalog/category/racks_srafsrafdsrafk Free files (CC BY 4.0, Xem Studio; STEP + STL, 3 parts): https://xemstudio.com/files/hardware/gear-racks-iso-53-module-1-to-3/index.json API: https://xemstudio.com/api/geometry?object=gear-racks-iso-53-module-1-to-3