I liked speedy777's pump drill design, but I have a bunch of hex bit attached drill bits. I also found the knob at the top to not print well on my machine so I remixed it to work with a 5mm x 16mm x 5mm bearing that I had purchased a bunch of off of amazon. I redesigned the parts so they are not compatible with speedy's design.
I print it on a raft with no supports and it comes out quite nicely on my machines.

Bearings used:
Amico a13061400ux0831 10-Piece 625ZZ 5mm x 16mm x 5mm Shielded Deep Groove Radial Ball Bearing
https://www.amazon.ca/gp/product/B00EDK5GIE/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1