During a routine inspection of a sheave, a crane operator measures the groove's bottom diameter. For a 20 mm nominal diameter wire rope, the sheave groove should ideally be 20.5 mm. However, the measurement reveals a groove depth reduction of 1.5 mm from the nominal diameter due to wear. What is the impact of this wear on the wire rope and the required action?

Question: During a routine inspection of a sheave, a crane operator measures the groove's bottom diameter. For a 20 mm nominal diameter wire rope, the sheave groove should ideally be 20.5 mm. However, the measurement reveals a groove depth reduction of 1.5 mm from the nominal diameter due to wear. What is the impact of this wear on the wire rope and the required action?

Answer options:

• The sheave is acceptable; minor wear does not significantly impact rope life. ✅ The sheave will cause the rope to be pinched and abraded, requiring replacement.
• The sheave will allow for excessive rope movement, reducing fatigue resistance.
• The sheave groove is now too wide, causing the rope to flatten prematurely.

Correct answer: The sheave will cause the rope to be pinched and abraded, requiring replacement.

Explanation: CSA Z150, Clause 5.2.2.3, indicates that severe sheave wear, leading to a reduction in the groove's bottom diameter, will cause the wire rope to be pinched and abraded. This 'pinching' effect dramatically increases localized stresses on the rope, accelerates wire fatigue, and causes premature rope retirement. A 1.5 mm reduction in depth for a 20 mm rope suggests significant wear, necessitating the replacement or re-machining of the sheave to prevent damage to the rope.