GEAR-DESIGN TRENDS…1.1 PRELIMINARY DESIGN CONSIDERATIONS…2.1 DESIGN FORMULAS…3.1 GEAR MATERIALS…4.1 GEAR-MANUFACTURING METHODS…5.1 DESIGN OF TOOLS OF MAKE GEAR TEETH…6.1 THE KINDS AND CAUSES OF GEAR FAILURES…7.1 SPECIAL DESIGN PROGRAMS…8.1 APPENDIX MATERIAL…9.1