Question 651General Subjects - Assistant Engineer

The correct answer is C) Brass. Brass is a metal alloy composed primarily of copper and zinc, which can typically be drilled without the need for lubrication. Brass has relatively low hardness and good machinability, making it easier to drill compared to other metals like steel or tungsten. The softer nature of brass allows it to be drilled without the risk of excessive heat buildup or damage to the drill bit, which can occur when drilling harder metals without proper lubrication. The other options, such as tungsten (A), steel (B), and Monel (D), are generally harder metals that require lubrication during the drilling process to prevent excessive wear and tear on the drill bit and to ensure a smooth, efficient drilling operation.