Nilesh Zende(Patil) &Aniket Birajdar (Patil)T.y. Mechanical

◦ Defination:- The limit can be defind as, when two extreme allowable sizes, between which the actual size is contained are called limits.

◦ Limits are two extreme allowable sizes of a given dimensions.

1.Maximum limit of size:-The greater of two is known as maximum limit of size.

2.Minimum limit of size:-The smaller of two is known as minimum limit of size.

Defination:- degree of tightness between two parts.

OR relationship between two existing

parts(i.e.shaft and hole)

1. Clearance Fit2. Interference Fit3. Transition Fit

Always has a gap between two mating parts.

Shaft size is small , compared to hole size. Generally in this type of fit, the lower limit

size of the hole is greater or at least equal to the upper limit size of the shaft.

Use:- pivots , latches fit of parts exposed to corrosive effects etc.

It is a fit where both clearance and interference may occur in the coupling.

Here tolerance zones of the hole and shaft are partly or completely interface.

Use:- Pulleys and bushing, Flushed bolts etc.

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

The upper limit size of the hole is smaller or at least equal to the lower limit size of the shaft.

Use:-In bearing bushings,flanges etc.

Defination:-It can be defined as the total permissible variation of size

OR The difference between the maximum limit

and minimum limit

1. Unilateral tolerance:-varition is permittedin an direction only from the design size or zero line.

2. Bilateral tolerance:-variation is allowed in both directions from the design size or zero line.

1. www.engineering fitsandtolerance.com