Clearance and interference coupling fits: Tips on when to use and how to determine tolerances
Couplings for connecting shafts can be placed in two categories: keyed and keyless. Similarly, the fits of couplings to shafts can be categorized as clearance or interference. A keyless coupling arrangement will always have an interference fit, while a keyed arrangement may have either a clearance or an interference fit. This article will focus on determining when to use a clearance or an interference fit, and how to obtain the tolerances for the resulting fit.