EMM Chapter 1 System of Limit & Fit

Basic size is

• the size of the component by actual measurement after it is manufactured

• a number expressed in a particular unit in the measurement of length

• the size based on which the dimensional deviations are given

• the extreme permissible sizes within which the operator is expected to make the component

There are three (3) types of fit which are:

• Interference

• Allowable

• Transition

• Clearance

Press fit, heavy drive fit, and shrink fit are examples of

• Clearance fit

• Transition fit

• Interference fit

Choose the disadvantages of limits, fits, and tolerance.

• The cost of pieces is reduced

• Initial expenditure will be very high

• Jigs and fixtures are needed

• Special purpose machines are necessary

Which one of the following is INCORRECT?

• Lower deviation is the algebraic difference between minimum limit of size and its corresponding basic size

• Upper deviation is the algebraic difference between minimum limit of size and its corresponding basic size

• Deviation is the algebraic difference between a size, to its corresponding basic size. It may be positive, negative or zero

• Actual deviation is the algebraic difference between actual size and its corresponding basic size

All internal features of a component including those which are not cylindrical is called

• shaft

• workpiece

• limit

• hole

....................... is where the size of the hole is kept constant and the size of the shaft is varied to get the different class of fits.

• Hole basis system

• Shaft basis system

• Limit basis system

• Tolerance basis system

The feature has basic size of 37.00, the upper limit of 37.50 and the lower limit of 37.40. It falls under

• Tolerance limits

• Bilateral limits

• Unilateral limits

The feature has an upper limit of 25.18 and lower limit of 25.10. The tolerance is

• 0.15

• 0.10

• 0.05

• 0.08

The figure shows the

• Unilateral limits

• Bilateral limits

• Tolerance limits