Which of the following is an interference fit?

Explanation:

Fit:

• It is the relationship that exists between two mating parts, a hole and a shaft, with respect to their dimensional differences before assembly.

Types of fits:

Clearance fit:

• It is a fit that always provides clearance.
• Here the tolerance zone of the hole will be above the tolerance zone of the shaft.
• There are five types of clearance fit:
  • Slide fit
  • Running Fit
  • Loose Running Fits
  • Easy Slide and
  • Location clearance fit

Interference Fit:

• It is a fit that always provides interference.
• Here the tolerance zone of the hole will be below the tolerance zone of the shaft.
• There are three types of Interference fit:
  • Force Fit
  • Tight Fit and
  • Shrink Fit

Force fit:

• To mating the high interference fit, requires a very high temperature for heating the part to assemble the shaft with a hole.
• The external force is required for the mating parts. Example: Gears, shafts, etc.

Tight Fit:

• It provides minimal interference than force fits. Example: Stepped pulley of a conveyor, cylindrical grinding of a machine, etc.

Driving fits:

• It requires medium interference which can be assembled by higher forces for cold forging or hot forging. Driving fits are more reliable than tight fits.

Example: Shafts, gears, bushes, etc.

Transition fit:

• It is a fit which may sometimes provide clearance, and sometimes interference.
• When this class of fit is represented graphically, the tolerance zones of the hole and shaft will overlap each other.