Oilers/Plant Tenders (HHC) Civil Service Practice Exam

What is a recommended method for removing a "shrink fit" collar from a shaft?

1. Applying cold temperature to the collar

2. Driving out the shaft after heating the collar only

3. Using a hacksaw to cut the collar

4. Water cooling method

The correct answer is: Driving out the shaft after heating the collar only

The preferred method for removing a "shrink fit" collar from a shaft involves heating the collar. When the collar is heated, it expands due to thermal expansion, which reduces the interference fit between the collar and the shaft. This allows the collar to be removed more easily without causing damage to either component. While heating the collar is indeed essential, driving out the shaft itself after heating may not be the most effective approach. Instead, it is typically recommended to either pull the collar directly from the shaft or use a combination of heating and cooling methods on the shaft, such as heating the collar and cooling the shaft, to facilitate removal. The other methods listed may not provide the efficiency or safety necessary for this kind of removal, as cutting the collar can lead to potential damage or misalignment, while applying cold temperatures to the collar alone may not effectively loosen it.