Electric driver gear Remix

This is a combination of a handle replacement with a electric screw driver gear with any short bit; demo: https://youtu.be/sMehUBvbXOU
If had made it already, there is also a add-on gear : http://www.thingiverse.com/thing:2123525
There seems some problem about the merge boundary for the handle, here is a fixed remix: http://www.thingiverse.com/thing:2172821
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2018/5/7 update: Add a gear/bit combination "MachineViseBit2", 50%+ infill recommended.