Explain the following terms: a. Tolerance b. Actual size c. Upper limit d. Lower limit e. Unilateral dimension f. Force fit – NABTEB QUESTION

1. Tolerance: This is the difference between the upper and lower limit of any dimension. It is the amount allowed for imperfection. e.g.

Upper limit – lower = Tolerance

2. Actual Size: This is the real dimension given to any component outside the limits. I.e (20+ 0.01) mm. 20mm is the actual size of the component.

3. Upper Limit: This is the maximum limit on any dimension.

4. Lower Limit: This is the maximum limit on any dimension,

5. Unilateral Dimension: This is the limit given on one side of the dimension e.g. ++ or –

6. Force Fit: This is the type of fit in which the shaft is slighty bigger than the hole and as such little force is needed to fit the shaft into the hole e.g. the biro and the cork.