| 摘要 |
A drill bit for producing drill holes with an undercut and comprising a drill bit shank, a drill bit tip mounted at an end of the drill bit shank and projecting laterally beyond the shank diameter, a rounded collar spaced from the drill bit tip and integrally formed on the drill bit shank, and a longitudinally displaceable sleeve mounted between the drill bit tip and the collar and having an internal diameter which is smaller than the diameter of the collar and the maximum width of the drill bit tip, and a method of manufacturing such a drill bit.
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