Millingspeeds and feeds chartpdf

The Magnum Super Premium drills will substantially outperform cobalt drills in work hardening stainless steel applications. This performance advantage is the result of construction differences between the two types of drills. Cobalt drills, manufactured to Type J NAS907 specs, has a very thick web. This web is necessary to limit breakage of the brittle cobalt steel. Magnum Super Premium drills are made of special Hi-moly tool steel, which is much tougher than cobalt steel. The web on a Magnum Super Premium drill can be thinned considerably due to the toughness of the steel.A Magnum Super Premium drill with its thin web will penetrate the work hardening stainless fast enough to continually cut beneath the chip which is hardening from deformation. This means the drill is cutting softer steel. The cobalt drill, with its thick web, cannot be fed at a fast enough rate to cut beneath the area which is hardening. As a result the cobalt drill is continually drilling into hardened steel.

Speeds and feedsformula

This microstructure is called pearlite, and the change is called the eutectoidic transformation. Pearlite has a diamond pyramid hardness (DPH) of approximately 200 kilograms-force per square millimetre (285,000 pounds per square inch), compared with a DPH of 70 kilograms-force per square millimetre for pure iron. Cooling steel with a…

Millingspeeds and Feeds chartMetric

…leads to the formation of pearlite, which in a microscope can be seen to consist of alternate laths of alpha-ferrite and cementite. Cementite is harder and stronger than ferrite but is much less malleable, so that vastly differing mechanical properties are obtained by varying the amount of carbon. At the…