CMRT Practice Test 2025 – Complete Exam Prep

The failure of a pillow block bearing due to an undersized shaft can lead to a broken cam because an undersized shaft might not provide adequate support for the components it is designed to accommodate. When the shaft does not fit properly in the bearing, it can lead to an imbalance and undue stress on the connected components, such as the cam. This stress can cause the cam, which may be made from more brittle materials, to fracture.

In this context, other options might involve different types of wear or failure mechanisms that are not as directly related to the size of the shaft. Seat wear, for example, would suggest issues with the fit or wear of the bearing itself, rather than a direct consequence of the shaft being undersized. Fractured housing might imply that the overall structure was subjected to stress, but it does not specifically connect to the implications of an undersized shaft. Excessive wear describes a general degradation of materials over time, which might occur but does not specifically relate to the immediate consequence of an undersized shaft affecting the cam. Thus, the correct choice underscores the direct consequence of the mismatch in sizing.