Makita impact driver magnetic bit holder accessory

After reviewing 4 or 5 other models, I decided to design my own which suits my needs more closely (and also I think is better in every way 🤔).

There are some funky ones that hold more bits (e.g. some protruding out the bottom) but I preferred all bits pointing upwards.

✅ Holds 7 bits in a row (others hold 4, 5, or 6)
✅ Print without supports
✅ Glue not needed
✅ No faffing around with inserting magnets halfway through print - just pop them in from the side after it's printed and they will stay there
✅ Bit holes are just big enough to allow for placement / removal without any friction, giving a satisfying magnetic “click”

You will also need:

✅ 6x3 magnets (similar to other models)
✅ Tweezers or something thin to poke magnets in from the side
✅ M4 screw (10-12mm long, any head type)

Instructions / what I did to get the tolerances just right:

1. Flip the STL (rotate on X axis) so it prints upside down. Then if you have a textured bed, the nice texture shows as you look down at it. (Also the geometry is designed to be printed upside down.) I presented it here un-flipped, otherwise it would look strange on the pics.
2. It was designed to print at 0.2mm layer height, if you go bigger then some overhangs etc might not print well. FYI, I printed on MK3S with Prusament PLA, enclosure doors open, and bridging was all fine.
3. When print finishes, shove a bit into each hole and wiggle it around furiously just to remove any fine strands and loosen the holes a bit. Use a bit extender for extra leverage.
4. Shove magnets into the little rectangular holes. Push them all the way, they will stop in the right place. Also as there's a little indent, they will stay there and not come back out.
5. Also I needed to remove a few fine hairs on the print, but nothing more than running my thumb over the surfaces.

Also if you have a longer / shorter screw, I can provide alternate countersink depths, PM me.

Notes about screws:

(1) Designed to work with pan-head screw where the head diameter is 9.7 (quite wide). Other models didn't fit this type of screw. Interestingly the screw supplied by Makita for the belt hook is about 9.1mm and other models didn't even fit that one - weird.

(2) Advice: remove battery before screwing into side. On my driver at least (TD173) if you screw a really long screw in, it will just protrude through the side of the driver and into the battery casing. I suspect it would pierce the battery if you use a long enough screw. The 10-12mm screw I have spec'd is nowhere near. But it's always best to be remove battery and inspect before screwing into the provided hole, just in case.