DIN 8000:2025-02

This document defines terms, design dimensions, and deviations of hobs for involute gears. The explanations refer to cutters with both unmodified and modified reference profiles. The essential contents and parameters of this document are also applicable to cutters with special profiles, for example for the manufacture of worms and worm wheels (flank shapes A, C, I, K, and N, see DIN 3975-1), sprockets (DIN 8190, DIN ISO 606), splined shafts (DIN 5471, DIN 5472), of serrated gears (DIN 5481) and of rotors. The differences are not explicitly explained. The standard differs from DIN 8000:1962-10 as follows: a) the title and structure of the document have been adapted to the specifications of DIN 820-2, the essential basic structure with "4. Explanation of terms" (formerly: "1. Introduction"), "5. Design dimensions" (formerly: "2. Basic terms for design dimensions") and "6 Deviations" (formerly: "Basic terms for the errors of a hob cutter") has been retained; b) Clause 4, Consideration of milling cutters with multi-start enveloping screws, results in significant adjustments both in the description of the design dimensions in Clause 5 and in the definition of deviations in Clause 6; c) Clause 5, inclusion of reference profiles with modifications, in particular specifications for hob reference profiles with protuberance and head edge beveller (further modifications, such as profile roundness, are possible); d) Clause 6: Inclusion of the term "measuring axis" and reference to uncertainty components of the measurements, significant changes to the definitions of deviations by taking into account multi-start envelope screws, and introduction of further descriptive parameters for deviations of modified reference profiles. This document has been prepared by Working Committee NA 060-34-11 AA "Zylinderräder - Terminologie und Toleranzen" ("Cylindrical gears - terminologies and tolerances") of Technical Section Gear at DIN Standards Committee Mechanical Engineering (NAM). Representatives of manufacturers and users of hobs and universities contributed to its preparation.