Bosch GSR Bit Holder (Cordless Drill/Driver)

I liked the Bit-Holder for cordless screwdriver (Bosch) and had used it for several month, until eventually it broke recently as it has a weak spot at the right arm.

As anyway the original was way too tight (had to scale up and expand the hex holes to be able to push in the bits, see make), I decided to create my own remix with better fit, smoother edges and a more symmetric design. But I kept the nice idea of mounting it to the small slots on the left and the screw hole on the right side.

After first test prints I realized, that magnets are not really needed if the bit holes are scaled right and slightly tapered (only 0.5°), i.e. narrower at the bottom than at the top. Bits do not fall out even if rotated upside down (see photo) and still can be pulled out with two fingers. And I also changed the design so that the M5 nut can be inserted after the print, so there is no more need to stop the print in the middle and model can be rotated to use way less support. (I thought about designing it without any support, but that wouldn't have really reduced the amount of required filament any further. Current model can be printed with less than 6g or 2m of filament (see Cura calculation)

For those who prefer a version with magnets (6x3mm), I added a version with non-tapered hexagons where magnets can (have to) be inserted during print (upright print orientation requires more support). In this case only please stop the print after 17mm (layer 85 with 0.2mm layers). The non-magnetic version can be printed in any preferred orientation without stops. Compared to the original design I reduced the layers on top of the magnets. There is no point in shielding them more than necessary.

For those who don't have a M5 screw and nut at hand, I also added a M5x15 screw with a flat head and an M5 nut. I did not embed the nut directly into the design, because threads should always be printed upright for better accuracy of the print (much better resolution in z direction). So please use adaptive layers or a small layer height when printing the screw and nut for perfect thread. (And for the screw I recommend 100% infill). The screw has an 8mm hex head - and I added a slot so you can even screw it in with your fingernail :-) 
(BTW: although one picture shows a normal metal M5 nut, I mounted the holder to the drill with the printed one (so that actually works), but that would have been rather invisible on the photo)

I use the bit holder with the old 10.8V version of the Bosch GSR cordless drill/driver and according to pictures I found it should also fit to the newer GSR-12V-15 version.
Unfortunately it does NOT fit to the GSB-120-LI hammer drill version (which I meanwhile own as well), because Bosch has slightly modified the design. (I might upload another version later)

Update (2023-07-30): As requested by @AiRLAC_2011, I've uploaded a slightly modified version with a stronger screw arm. (I must admit, the walls were rather thin, but I never had issues with it). The frame around the screw hole is now +1.2mm wider and the wall under the screw +0.6mm thicker…. and then a few hours later I added yet another “extra sturdy” version on request, where also the other side has been thickened by 0.8mm (never had issues with it so far - but if you really try to break something applying force, you might succeed with the original design. I hope the update withstands longer )

Update (2023-010-03): Uploaded STEP file of the sturdy version as requested by @MBart_304769

Recommended Print Settings:

The version without magnets is best printed on the back, which minimizes the required support. Unnecessary support could also be avoided by setting the Support X/Y Distance to 2.5mm and Support Overhang Angle to ≥ 70. With these settings I didn't even need support blockers for the holes. 

For the version with magnets this is different, because it has to be printed upright and print has to be stopped after 17mm/layer 85 to insert the magnets.

0.2mm layer height and 20% infill is fine (except for the screw where I recommend 100% infill). The print with even less than 6g also used adaptive/variable layer height to get a smooth curved surface.