A proper fitting sheave groove should support the rope over which degree range?

The appropriate fitting sheave groove should support the rope within a degree range of 135 to 150 degrees. This range is crucial for ensuring optimal contact and support for the rope, allowing for effective weight distribution and minimizing wear on both the rope and the sheave itself. A groove that fits within this angle range promotes the ideal curvature that aligns with the rope's natural bending patterns during movement and load transfer.

A proper fit within this angle also helps to prevent issues such as rope slipping or excessive friction, which could lead to premature wear or failure. This is especially important in millwright rigging practices where loads can be substantial and safety is paramount.

In contrast, other ranges would not provide the same level of support or could cause mechanical failures. Maintaining the proper degree range of 135 to 150 degrees in a sheave groove is fundamental in ensuring both the longevity of the rigging equipment and the safety of operations.