Gears
Modules for spur gearsISO 54 (JIS B 1701-2:2017)Standard values of the normal module for spur and helical gears. Two tables are listed, one for 1 mm and above and one for below 1 mm.Modules for straight bevel gearsISO 678 (JIS B 1706-2:1999)Standard values of the module and the diametral pitch for straight bevel gears. Standard values below 1 mm are listed as well.Gear tooth contactFormer JIS B 1741-1977 (withdrawn)The proportion of tooth contact along the lead and along the tooth depth, given in three classes, A, B and C. Three kinds are covered: cylindrical gears, cylindrical worm gears and bevel gears.