True or false: In milling, feed is defined as distance per tooth.

• A. True
• B. False
• C. It is distance per revolution
• D. It is the depth of cut per pass

Answer: (A)

In milling, the feed is how far the workpiece advances for each tooth of the cutter as it engages the material. This distance per tooth, called feed per tooth, is the basic measure of how much the tool advances with every tooth that passes. The overall feed rate you program on a machine is found by multiplying this distance per tooth by the number of teeth on the cutter and by the spindle speed (rpm), giving you inches (or millimeters) per minute. For example, with a 4-tooth cutter and a feed per tooth of 0.01 in, at 3000 rpm, the feed rate would be 0.01 × 4 × 3000 = 120 in/min. Distances per revolution and depth of cut per pass refer to other aspects of the operation, not the feed per tooth.