“Secondary operations” refer to modifications made to a stock or semi-finished gear after its initial manufacturing, such as modifying bore sizes, adding keyways, set screw holes, or applying surface treatments. This is often a faster and more cost-effective alternative to designing a fully custom gear from scratch. For example, a manufacturer may stock standard gears with basic dimensions and then absorb specific specification differences by modifying those standard parts to meet individual customer needs .
However, there are important limitations.
- First, not all modifications are possible—some manufacturers cannot produce gears with smaller bores than their stock versions due to manufacturing capacity constraints.
- Second, when adding features like keyways after cutting, precise positional alignment between the keyway and gear teeth is difficult. The positioning accuracy is often only within ±0.1mm, as it is done by scribing rather than CNC-controlled indexing.
- Third, secondary surface treatments like plating can affect dimensions unpredictably—plating films are only a few micrometers thick but may impact shaft insertion in precision bores.
Always confirm your specific modification requirements with the manufacturer before ordering.