This is a quick to print, handy little thing to hold my hex shank drill bits. I use these in my screwdriver/electric screwdriver for post processing prints. It lets me see the numbers on the side of the bits too. The bits are snug, but not held tightly. Scale it down 1-2% for a friction fit (tested). This is the bit set in the picture, they're not amazingly sharp but good enough for plastic. http://www.ebay.co.uk/itm/370962314440?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 Done in ABS, PLA will work better but not as nice a finish! 0.2mm layers +5 degrees nozzle temp (for laminar adhesion) 60% infill 5mm brim