Question

what is used to rate the coarseness of a band saws blade?
revolutions per minute
teeth per inch
hardness of the blades teeth
length of the blades teeth

Explanation:

Band saw blade coarseness is rated by teeth per inch. Fewer teeth per inch mean a coarser blade for faster cutting of thicker materials. Revolutions per minute relate to blade speed, not coarseness. Hardness of blade's teeth affects durability, not coarseness. Length of blade's teeth is not a standard rating for coarseness.

Answer:

teeth per inch