Hole Basis system and Shaft Basis System

Hole Basis system: If the system of assembly of shaft and hole is consisting of basic hole, then that type of system is known as Hole Basis System. It means for the system of assembly of shaft and hole, the zero line will be lying on the minimum diameter of the hole as shown figure. For this system the lower limit size of hole is equal to basic size.

Hole basis system

Shaft Basis system: If the system of assembly of shaft and hole consisting of basic shaft, then that type of system is known as Shaft Basis System. It means for the assembly of shaft and hole, the zero line will be lying on the maximum size of the shaft as shown. For this system the Upper Limit Size of shaft is equal to the Basic Size.

Shaft Basis System