| 摘要 |
An annular hole cutter having a plurality of teeth spaced circumferentially around the lower end thereof. Each cutting edge has a radially inner portion and a radially outer portion. The two portions of the cutting edges are preferably spaced apart vertically and circumferentially and disposed such as to form positive side rake angles relative to the inner and outer peripheries of the cutter. Each tooth has associated therewith an inner gullet and an outer gullet designed to permit the free passage of chips upwardly away from the two portions of the cutting edges. |
