Sadly I could not find the original designer of the handle to credit them. If you can find the model let me know and I'll update the description. I've improved the original handle design by adding an angled part in each gap for grip. They were 90 angles in the original model and had very poor results printing. The caps/bases are used unmodified.
The other major improvement is the handrest. There are 3 of them sized for 30mm, 40mm, and 50 mm bases. This makes it easier to steady your hand while painting, reducing mistakes. The thickness of the handle also makes it easier to use 1 handle for multiple minis. 2 spins will remove a cap so you can quickly put another one one. Using caps keeps the mini's more stable than using multiple handles or dowels that can easily.
It's also easy to reposition the mini. Loosen the cap, spin the arm to where you will need it to be, tighten down the cap, adjust your grip on the mini.
Printing Instructions: I find that all parts print best at 12mm layer height anywhere threads and angles occur. I recommend 15-25% infill since all parts will experience pressure from either a hand resting or the force of twisting the cap. Bases/caps print best upside down to avoid bridging. Using a textured build plate will help stick tack adhere. Support arm should be printed in it's side.
Assembly Instructions: Support arm slots into the support base. It can take a bit of pressure and wiggling to get it in, but no glue needed to keep it secure.
The author remixed this model.
Modified the hand rest arm to be a loop around the threaded part of a different handle. Resized to account for multiple base sizes.