It is the lack of any drills often drill in the Chuck begins to rotate, especially when exiting from the drilled hole. And in electric drill drill bit you can still firmly hold a special knob in the manual is not easy to do. Therefore, readers will probably be interested in a little improvement which I have used for a clamping Chuck of the tool. The hall hand microdrile screw a regular nut (key 19) and secured it on the threaded pin M4, and on the cartridge with a handsaw and made two flats on turnkey 22. This upgrade allowed two wrenches to firmly secure the drill bit.
You can use another option: if the cartridge consists of two parts on the thread, it is enough to make the same the flats of the inner disk cartridge.
A — option with flats on the Chuck and mounted on a shaft nut. B — variant with flats on both parts of the cartridge.
This upgraded me wrench use for many years and find it very comfortable. Drilled in the jaws of the hole and zapressovan there are two steel pins universal tool to Unscrew also hidden and castle nuts of different sizes.
E. MATASOV, Moscow