Sometimes you need to use a 1/4" screwdriver bit for a precision security screw or something that requires finesse and minimal torque. Taking apart handheld electronics and removing security screws can be extremely difficult using a normal sized screwdriver handle.
This driver handle is designed to make using 1/4" hex bits on precision screws much easier and give the user much more control. It has an ergonomic shape and a free spinning tail-cap that rests comfortably in the palm. There is storage behind the cap where an additional bit or two can be stored.
Directly behind the bit, there is an optional spot for adding a neodymium magnet. Adding a magnet will prevent the bit from falling out after prolonged use ( Source for magnets: http://a.co/gu1ftkJ ).
The cap should snap on with a firm press. Sometimes depending on your printer and print settings, the lip on the cap may require a light sanding (see picture). After the cap is installed, spun, and taken on/off a couple times, it should install and move smoothly. Wax can be added to bottom of cap to make spinning even smoother.
a 5mm x 3mm magnet can be installed in the handle by centering the magnet on the back of a bit before inserting it into the handle. Once the bit bottoms out, use the handle to firmly push the bit against a hard surface. This will force the magnet into place.
The tolerances required for the bit easily going in and staying in are very tight (.1mm). I have modified the Hex opening with a different taper/draft. The new version works very well even without a magnet.
UPDATE: Check out the remix version designed to accommodate Double Ended Bits
Most printers should not need supports to print these parts. Print the handle and cap with the larger diameter end on the bed (see picture).