ALLOWANCES AND TOLERANCES FOR HOLE AND SHAFT ASSEMBLY

Introduction:
The selection of allowances and tolerances for the hole and shaft assembly is an important task in the design of mechanical parts. This helps to ensure that the parts fit together properly and function as intended.

Dimensions of Mating Parts:
Hole: 25±0.05, -0.00
Shaft: 25-0.02, -0.05

Allowance:
The allowance is the intentional difference between the maximum size of the hole and the minimum size of the shaft. It determines the amount of interference or clearance between the mating parts. In this case, the allowance can be calculated as follows:

Maximum Hole Size = 25.05
Minimum Shaft Size = 24.98
Allowance = Maximum Hole Size - Minimum Shaft Size
Allowance = 25.05 - 24.98
Allowance = 0.07 mm

Therefore, an allowance of 0.07 mm should be used for this hole and shaft assembly.

Tolerance:
The tolerance is the permissible variation in the size and shape of the mating parts. It ensures that the parts can still function properly even if there are small deviations from the nominal dimensions. In this case, the tolerance can be calculated as follows:

Hole Tolerance = Upper Limit - Lower Limit
Hole Tolerance = 0.05 - 0.00
Hole Tolerance = 0.05 mm

Shaft Tolerance = Upper Limit - Lower Limit
Shaft Tolerance = 0.02 - 0.05
Shaft Tolerance = 0.03 mm

Therefore, a hole tolerance of 0.05 mm and a shaft tolerance of 0.03 mm should be used for this hole and shaft assembly.

Conclusion:
In summary, the selection of allowances and tolerances for the hole and shaft assembly is critical to ensure proper fit and function of mechanical parts. For the dimensions of mating parts provided, an allowance of 0.07 mm and tolerances of 0.05 mm for the hole and 0.03 mm for the shaft should be used.

L.L of hole = 25.00
H.L of hole = 25+0.05=25.05

hole tolerance =H.L - L.L
>>>0.05

L.L of shaft = 24.95
H.L of shaft= 24.98
>>>0.03


Allowance = L.L of the hole - H.L of the shaft
>>>0.02

Minimum clearance = L.L of the hole - H.L of the shaft
>>>0.02
Maximum clearance =H.L of the hole - L.L of the shaft
>>>0.1


>>> the H.L of the shaft is less than the L.L of the hole is CLEARANCE FIT