4mm bit precision screwdriver / bitholder

Precision screwdriver description:

I didn't like the way most precision screwdriver felt (especially the end cap) so I made my own with a ball beared end cap using a 687 Bearing. I like the upper part of the LTT precision screwdriver, which is why this design ended up as a mix between an LTT and iFixit screwdriver.

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Bearings :

For the bearing you can either use a normal 687 ball/slide bearing or a 3D-printed one.           I used this one https://www.thingiverse.com/thing:4851975/files 

(you need the Bearing_687_slide_tolMin.stl)

Shaft:

The metal shaft is not needed but obviously makes the screwdriver more durable and comfortable to use. If you don't have/want to buy a shaft you can just print the screwdriver_handle_without_shaft.stl. Theoretically you can glue a 4mm magnet in the shaft.

The shaft I used came with a other cheap screwdriver (also often used as extensions) but you can buy ones with magnets here:

Amazon: https://www.amazon.com/-/us/dp/B0CWLJYCZD/ref=sr_1_6?sr=8-6 

Aliexpress: https://www.aliexpress.us/item/3256803851346107.html?channel=twinner   

(I try to update these links but if they aren't working just search for 4mm bit extensions, they should be round 120mm long (the linked ones are 123mm long))

If your printer has half-decent accuracy the shaft/bits should be a tight, but not too tight fit (Let me know how the fit is for you!)

How to print:

Print it in the following orientation with a low layer height so the knurled texture turns out good.

For the end-cap i would print like this with suport so it feels better in your hand.