4mm Mini Magnetic Hex Bit Holder Driver

After creating the ¼" 6.35mm hex bit holder I realized I needed another for the smaller bits. Great for tiny sewing machine screws in tight places. 

The other one: https://www.printables.com/model/1469950-mini-magnetic-hex-bit-holder

The cylindrical shape helps keep the bit perpendicular to the screw. The knurling helps with grip. The recessed top allow a finger to press it onto the screw and keep it centered.

16mm in diameter. 27mm tall. 12mm hex recess depth. 15mm finger recess radius. 

Insert a 10mm diameter magnet less than 3mm thick into the lower portion and glue the top on.

For this driver's bigger sibling: