The type of fut between a mating shaft of diameter ${25.0}^{\begin{array}{c}+0.010\\ -0.010\end{array}}$mm and a hole of diameter ${25.0}^{\begin{array}{c}+0.015\\ -0.015\end{array}}$mm is _________

The correct option is Transition.

1. Understanding the Fit Concepts:
In engineering metrology and design, fits describe the relationship between two mating parts (a hole and a shaft) before assembly. There are three primary types of fits:
• Clearance Fit: The tolerance zone of the hole is entirely above the tolerance zone of the shaft. The hole is always larger than the shaft, resulting in a clearance.
• Interference Fit: The tolerance zone of the hole is entirely below the tolerance zone of the shaft. The shaft is always larger than the hole, requiring force to assemble.
• Transition Fit: The tolerance zones of the hole and shaft overlap. Depending on the actual size of the manufactured hole and shaft, the fit may result in either clearance or interference.

2. Analyzing the Limits from the Attached Diagram:
Looking at the provided diagram, we can read the limit dimensions directly:
• Hole Limits:
Upper Limit of Hole = 25.030 mm
Lower Limit of Hole = 25.000 mm

• Shaft Limits:
Upper Limit of Shaft = 25.010 mm
Lower Limit of Shaft = 24.990 mm (indicated as 24.99 in the diagram)

3. Step-by-Step Calculation (Diagram Values):
Let us calculate the maximum and minimum clearance or interference:
• The maximum possible clearance occurs when the hole is at its largest limit and the shaft is at its smallest limit:

$\text{Maximum Clearance}=\text{Upper Limit of Hole}-\text{Lower Limit of Shaft}$

$\text{Maximum Clearance}=25.030-24.990=0.040\text{ mm}$
(Since this value is positive, it represents a clearance).

• The maximum possible interference occurs when the shaft is at its largest limit and the hole is at its smallest limit:

$\text{Maximum Interference}=\text{Upper Limit of Shaft}-\text{Lower Limit of Hole}$

$\text{Maximum Interference}=25.010-25.000=0.010\text{ mm}$
(Since this value is positive, it represents an interference).

4. Step-by-Step Calculation (Alternative Question Text Values):
If we calculate using the dimensions given in the question text:
• Hole: ${25.0}^{+0.015/-0.015}\text{ mm}$ (Range: 24.985 mm to 25.015 mm)
• Shaft: ${25.0}^{+0.010/-0.010}\text{ mm}$ (Range: 24.990 mm to 25.010 mm)
• Maximum clearance:

$25.015-24.990=0.025\text{ mm}$

• Maximum interference:

$25.010-24.985=0.025\text{ mm}$

In both cases, because the assembly can result in either clearance or interference depending on the actual sizes of the individual parts, the fit is classified as a Transition fit.