High School

The tool commonly used for testing the hardness of metal before cutting it with a hacksaw blade is a hardness tester.

Answer :

Final answer:

A hardness tester is the tool used to test metal hardness before cutting it with a hacksaw blade, ensuring the selection of an appropriate blade for the material.

Explanation:

The tool commonly used for testing the hardness of metal before cutting it with a hacksaw blade is called a hardness tester. This tool helps to determine if the hacksaw blade can effectively cut the metal or if a different tool should be used. Hardness testers come in various forms, including portable models that can be used directly on the shop floor. When cutting metal, it's important to match the hacksaw blade to the material's hardness to ensure efficient cutting and to prevent damage to the blade.