A drill feed is the rate that a drill bit is inserted into an object in order to bore a hole. This factor is typically tied very closely to drill speed, which is how fast the bit is rotated. Drill feed is usually represented in a figure such as millimeters or inches per revolution, so if the drill speed is changed then the feed rate must be as well. A proper drill feed rate can be determined by a number of factors, such as the drilling equipment, composition of the bit and the material the workpiece is made of. Some materials require slower drill feeds, while others can accept higher feeds but require more power from the drilling equipment.
Feeds and speeds is a machining term that can be used in a number of different circumstances. In each case, the term refers to feed rate and cutting speed, which are two interrelated factors. Feed rates typically refer to the moving component in a system, and can be expressed in values of distance over time for linear processes such as milling, or distance per revolution in machining applications that involve rotation. Since drilling is a process that involves a rotating bit that is used to bore a hole, this type of machine work is considered to be a rotating application.
The feed rate of a drill is simply the velocity with which it is fed into a workpiece. Each time the bit revolves one time, it is inserted further into the workpiece by a precise amount. If the drill speed is increased and the feed remains constant, the bit will be inserted at a faster velocity. This is due to the fact that the number of revolutions per second becomes higher when the drill speed increases, which in turn causes the bit to advance further with each passing second.
An appropriate drill feed rate can be calculated based on a number of factors, including the drilling equipment and the particular workpiece involved. The drilling equipment must be powerful enough so that the bit will not become bound in the workpiece, so a slower drill feed is typically necessary when dealing with low power units. Low feeds are also necessary when dealing with certain workpiece materials, which may collapse, splinter or break if excessive pressure is applied. The correct drill feed can also depend on the diameter of a drill bit and the materials from which it is constructed.