Elevator Mechanic Practice Exam 2025 - Free Elevator Mechanic Practice Questions and Study Guide

The recommended materials for the worm and worm gear in a geared machine are typically bronze and steel. Bronze is chosen for the worm gear primarily due to its excellent wear resistance and antifriction properties, which are important in minimizing wear during the engagement with the steel worm. The use of steel for the worm provides the necessary strength and durability to handle the loads and stresses encountered during operation. This combination ensures optimal performance and longevity of the geared machine.

The other material options do not offer the same balance of strength and wear resistance. Copper, while having good conductivity, is not as robust for load-bearing applications. Gold is a precious metal that is not practical for mechanical components due to its softness and high cost. Iron, although stronger than some other materials, is susceptible to wear and corrosion compared to bronze. Therefore, the choice of bronze and steel is crucial for efficient and reliable functioning in geared systems.