29 tool bit spaces
1 handle space
4 bolt or other bins
1 larger bin for tweezers or other things
I heated up the end of the a tool bit just a bit (say 40degrees C) to press in the handle to make the fit really snug.
The handle fit is designed at 4.1mm
The tool bit spaces at 4.3mm
The handle is best printed standing on the open end with a two layer brim of 10mm.
I included the step file so you can adjust and remix up to your liking.
The photo's show version 1, I updated it a little to improve the overall usability!