Final answer:
It's recommended to use a new hacksaw blade to continue a cut started with a used one because a new blade ensures a sharp, efficient, and safe cutting process, whereas a used one may lead to rough cuts, increased effort, and safety hazards.
Step-by-step explanation:
When working on a cutting task with a hacksaw, it is essential to use a blade that is in good condition to ensure efficiency and safety. If a cut is started with a used blade, it's recommended to replace it with a new hacksaw blade to continue the job. This is because a used blade may have developed uneven wear or damage that can result in a rough cut, potentially damage the workpiece, increase the amount of effort required to saw, or pose a safety risk due to an increased likelihood of the blade breaking.
Using a new blade provides a sharp edge, which is crucial for a smooth, straight cut, and reduces the physical strain on the user. Moreover, since the teeth of a new blade are evenly shaped and sharp, the cut will be more precise, and there will be less chance of blade deviation that could cause an uneven or incorrect cut.