system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it necessary to have course thread bolts (UNC) and fine thread bolts (UNF)? Wouldn’t having only one or the other be just fine?
gpt
In general, coarse threads are easier to start and faster to screw in, while fine threads are stronger for a given base diameter. Having two options as widely available, standardized choices for each screw diameter allows engineers to pick a thread pitch which is most useful in the particular application they are designing for.