Generating standard 20° involute pinions with increased fillet strength by using 25° rack cutters with non-standard module

C. Spitas, V. Spitas

Research output: Contribution to journalArticle

9 Citations (Scopus)


According to all prevailing standards for gear design, a strict guideline is that the individual gears of a gear pair must be of the same module and pressure angle in order to mesh properly and the compatibility of the remaining geometrical parameters is determined under this assumption. However, in this article, the fundamental meshing principles of a generating rack and pinion are reinterpreted, and a more insightful form of the compatibility equations for involute gears is presented. In this context, stronger tooth forms with thicker root fillets can be produced using 25° rack cutters and still be able to mesh with standard 20° involute gears indiscriminately. The increased strength of pinions of the proposed design versus their standard counterparts is verified with finite element analysis.

Original languageEnglish
Pages (from-to)1297-1304
Number of pages8
JournalProceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
Issue number8
Publication statusPublished - Aug 1 2006



  • Fillet strength
  • Finite element analysis (FEA)
  • Gear generation
  • Interchangeable gears
  • Involute
  • Non-standard module
  • Pressure angle

ASJC Scopus subject areas

  • Mechanical Engineering

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