Which tool is recommended for shortening the length of CMUs instead of a mason's hammer?

Using a masonry saw to shorten the length of concrete masonry units (CMUs) is the most effective method due to its precision and ability to create clean cuts. A masonry saw typically features a diamond blade or a carbide-tipped blade specifically designed to cut through hard materials like concrete and masonry. This results in a more accurate and cleaner finish compared to other methods, minimizing the likelihood of cracking or damaging the CMU during the cutting process.

In comparison, while a masonry chisel can also be used to shape or adjust CMUs, it requires significant manual effort and can lead to uneven edges. A concrete grinder is better suited for surface leveling rather than cutting units down to size and can be cumbersome for this purpose. A hand trowel is primarily used for applying, spreading, and smoothing mortar, making it ill-suited for cutting CMUs altogether. Therefore, the masonry saw is recommended for achieving the best results when shortening the length of CMUs.