Catalog of standards
Catalog of standards | Group code | Title |
| 21.020 | Characteristics and design of machines, apparatus, equipment |
| 21.040 | Screw threads |
| 21.060 | Fasteners |
| 21.080 | Hinges, eyelets and other articulated joints |
| 21.100 | Bearings |
| 21.120 | Shafts and couplings |
| 21.140 | Seals, glands |
| 21.160 | Springs |
| 21.180 | Housings, enclosures, other machine parts |
| 21.200 | Gears |
| 21.220 | Flexible drives and transmissions |
| 21.240 | Rotary-reciprocating mechanisms and their parts |
| 21.260 | Lubrication systems |