| 摘要 |
To summarize, it may be stated that this application does not concern an auxiliary device but a complete precision instrument. The following are the main points for which patent protection should be provided: 1. The swivelling point must always be in the centre of the drill tip. 2. This drill tip centre is located rearwards, calculated from the drill tip, by half as many millimetres as the drill is thick. 3. This swivelling point must be adjustable for every drill thickness. 4. The swivelling arc is not to exceed about 30 degrees. 5. A stop disc must prevent the drill being able to displace forwards when it is reversed. 6. In order to be able to adjust the overall instrument exactly at the required distance from the grinding wheel, an auxiliary device in the form of two welded-together flat bars is required, which is held firmly on the grinding wheel by means of a clamp for the duration of the adjustment. d
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