Red Seal Machinist Practice Exam

What type of lubricant is typically employed during metal cutting?

1. Water

2. Oil

3. Cutting fluid

4. Grease

The correct answer is: Cutting fluid

Cutting fluid is specifically designed for use during metal cutting processes. It serves multiple functions that are essential for effective machining. One of its primary purposes is to cool the cutting tool and workpiece, which helps to dissipate heat generated during the cutting operation. Excessive heat can lead to tool wear, loss of dimensional accuracy, or even tool failure, so maintaining an optimal temperature is crucial. Additionally, cutting fluid assists in reducing friction between the cutting tool and the workpiece, resulting in improved surface finish and longer tool life. It can also help in flushing away chips and debris produced during the cutting process, preventing them from interfering with the machining operation and contributing to workpiece quality. While oils, greases, and water can have roles in lubrication and cooling, cutting fluid specifically combines both properties in a way that is optimized for machining operations. It is formulated with additives to enhance its performance in cutting environments, making it the preferred choice for metal cutting applications.