Correct option is B
The
box nut of a bench vice is typically made of
phosphorous bronze due to its excellent wear resistance, low friction, and good strength. Phosphorous bronze is an alloy of copper, tin, and phosphorus. The phosphorus content enhances the hardness and reduces wear, making it ideal for the threaded box nut that engages with the screw and withstands repeated sliding and clamping forces.
Phosphorous Bronze Properties:
· High wear resistance.
· Self-lubricating properties due to its low coefficient of friction.
· Excellent strength and fatigue resistance.
Purpose of the Box Nut: The box nut holds the threaded lead screw in a bench vice and transfers the rotational motion of the screw into linear movement for clamping.
Why Not Steel: Using steel-on-steel contact for both the screw and the nut can lead to excessive wear and galling (adhesive wear). Hence, a softer, wear-resistant material like phosphorous bronze is preferred.
Applications of Phosphorous Bronze: Commonly used in bearings, bushings, gears, and other components requiring low friction and high wear resistance.
