Final answer:
The speed range on mills or lathes should be set before the machine is turned on to ensure safe and efficient operation.
Step-by-step explanation:
The speed range on mills or lathes should be set BEFORE the machine is turned on.
By setting the speed range before turning on the machine, you can ensure that it is operating within a safe and efficient range. This is important because different materials and machining operations require different cutting speeds. For example, when working with a hard material like steel, a slower speed may be required to prevent overheating or tool breakage.
By properly setting the speed range before starting the machine, you can optimize the machining process and achieve accurate and high-quality results.