The motor sits in the center of the housing on a stationary shaft. On each side of the motor, an outer shaft drives the drill. When the handle is rotated, a very simple transmission slides the motor along the inner shaft, engaging the opposite facing outer shaft. Only one side of the drill is engaged at any time. Rotation of the handle also reverses the polarity of the motor, such that the direction of rotation is conistent on both sides of the tool.

Motivation: Having a drill bit in one chuck and a fastening bit in the other chuck eliminates the need for two drills or the nuissance of constantly switching bits.
-- ed, Jan 14 2010

Double Chuck Drill http://www.abc.net....rs/txt/s1361889.htm
This seems simpler. [WcW, Jan 15 2010]

That, if I may say so, is a neat idea. The ergonomics would be a pain to work out, though, and you might wind up with an unacceptably bulky/lengthy tool. [+]
-- MaxwellBuchanan, Jan 14 2010


When I'm drilling into brickwork I often like to press on the back of the drill with my spare hand, to put more pressure on the bit. Conventional drills are shaped to allow you to do this, but it'd be a lot harder with another axle and chuck in the way.
-- Wrongfellow, Jan 14 2010


I presume they'd stay on your favourite drill.
-- MaxwellBuchanan, Jan 14 2010


they have a double headed drill design now with both heads facing the front. To change the head you rotate it (on a 90* bevel) 180* and the other chuck is in front.
-- WcW, Jan 15 2010


WcW: Have you a link?
-- ed, Jan 15 2010


//you might wind up with an unacceptably bulky/lengthy tool// fnaar fnaar
-- hippo, Jan 15 2010


Linky. Also note that the patent on this is weak. Many rip off designs are already on the market from the asian region.
-- WcW, Jan 15 2010


[-]I might put my eye out!
-- Jscotty, Jan 16 2010


I like a quick-release, for close operation and steadiness while keeping balance and changing bits on the fly, but that is just me and on my own jobs. However, I may later try to affix a driver to the end of my hammer handle -- never seen one of those in stores.
-- reensure, Jan 16 2010


//[-]I might put my eye out!//

That is a good point. Imagine you're driving a screw into a pilot hole you've just drilled - you'll have a (non-rotating) pointy drill bit pointing straight at you.
-- MaxwellBuchanan, Jan 16 2010


As [MB] points out, this has some ergonomic issues, but it is still interesting. (+)
-- MisterQED, Jan 16 2010


I just thought of a better implementation: a removable chuck. A square shaft could protrude from the front of a one-sided drill. The user slides the chuck onto the shaft, rotating until it slides on. Once the chuck is properly engaged, a magnetic latch prevents the chuck from falling out, and a safety circuit is closed allowing the motor to be operated.

The point, of course, is you can keep a different bit in each chuck (one drill, one driver) to save time changing bits.
-- ed, Nov 28 2012


Don't seems to be safe...
-- piluso, Nov 29 2012


I have a nifty thing made by DeWalt, although I think Craftsman has one too: an oversized hex-bit receiver that holds a reversible doohickey with a driver on one end and a pilot bit/countersink on the other. Instead of changing chucks or transfering drives, you just pull the 'bit' out and flip it over.. It's great for hanging drywall, but it's made of almuminium and thus unsuitably delicate for fab work.
-- Alterother, Nov 29 2012


[ed] Removable chucks exist. Festool's, for example, has a hex drive and a bayonet type connection.
-- spidermother, Nov 29 2012


I also have a Bosch hammerdrill with a quick-change chuck. I forgot about that, probably because I haven't used it for five or six years. I have two extra chucks, which is handy for fab work because I can pilot, bore, and tap all with one tool. For some reason, they don't make them anymore.
-- Alterother, Nov 29 2012



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