When drilling metals, which lubricant is commonly used?

Oil is commonly used as a lubricant when drilling metals due to its ability to reduce friction and heat generated during the drilling process. By providing a slippery interface between the drill bit and the metal, oil helps to improve the efficiency of the cut, extends the life of the drill bit, and minimizes the risk of overheating, which can lead to tool wear or failure.

In addition to lubrication, oil can help flush away chips and debris produced during drilling, providing a clearer path for the drill bit and reducing the chances of binding or jamming. Certain oils, such as cutting oil specifically designed for machining, have additives that further enhance performance by improving cooling properties and reducing tool wear.

Other options, while they may have some lubricating qualities, are less effective in the specific context of drilling metals. For example, water can act as a coolant but does not provide sufficient lubrication for cutting operations. Alcohol and soap do not provide the necessary properties for effective lubrication in metal drilling, making oil the preferred choice in this scenario.