• A set of reasonable fits is suggested below,

shafts rotating under 600 rpm with ordinary loads; >RC5

shafts rotating over 600 rpm with heavy loads; < RC5

shafts sliding freely; approx. LC

push fits with keyed shafts and clamp, no fitting; LT

parts assmemble with some basic fitting; LN

Permanent assembly with no freely moving parts; FN1

permanent assembly with severe loading effects; FN3

permanent assembly with press needed for assembly; FN5



1.1.1 Clearance Fits


• A clearance fit always has a gap between the two mating parts.


• The diagram below shows a clearance fit between a shaft and a hole



1.1.2 Transitional Fits


• This type of fit may result in interference, or clearance


• This type of fit can be used for items such as snap fits


• The figure below illustrates this condition for a hole shaft pair




1.1.3 Interference Fits


• Interference fits always overlap and are used mainly for press fits where the two parts are pushed together, and require no other fasteners


• The figure below shows an interference fit for a hole shaft pair