Parametrised Bit Holder

UPDATE New SCAD file with improved rendering times - 2025-06-02

Intro

Parametrised screwdriver bit holder that can be printed in spiral/vase mode.

I found the 'Flex Bit Holder' project and was impressed by the cleaver use of spiral mode to slice it. This is more a total rework than a remix, but I wanted to credit the inspiration.

Hopefully, this will work with the online 'Customize' tool, but if not, OpenSCAD is easy enough to install. Be aware, it can take a while to render the object.

I've uploaded a selection of STL files to show what the expected output is like.

Usage

You can use the SCAD file to adjust various features, from the number of bits. the layout, the bit sizes, vent hole, and grip ring.

bits The number of bits
You can go as low as 1, and no set maximum, but I'd suggest keeping it less than 25 as OpenSCAD struggles on the larger renders
row mode Number of rows and their layout
You can select between 1, 2, and 3 rows. The 3 row option allows two forms, 'Trapezoid' and 'Rhombus'.
3 row renders flip between three layouts based on the number of bits.
- Multiple of 3 = A trapeze or rhombus shape, as selected.
- Multiple of 3 remainder 1 = A hexagonal shape
- Multiple of 3 remainder 2 = A 'bowtie' shape
bit dia The diamter of the bit. For 1/4" bits 6.8 should work. 4mm bits, use 4.4. And you're free to use whatever other value suits your needs
bit height The is the depth of the holes the bit will slot into. 10mm seems to work well for the standard bits, 15mm is good for impact driver bits.
bit grab A small ring used to help hold the bits in place. You can set this to 0 turn it off.
bit grab height The position, from the bottom of the bit slot, the grab is placed. I'd recommend keeping it fairly low down. Higher positions have the tendency to block the bit.
base height The thickness of the base. 0.9mm seems fine, other values may need a change in slicer settings.
base vent dia The size of the vent hole at the bottom of the bit slot. Needs to be smaller than the bit hole. 0 to turn it off.
format Select between 'Spiral/Vase' style, or 'Solid' if you'd prefer to print out without using spiral mode.

Print Settings

Material : TPU
Spiral mode : Check the output matches the example screenshot.
Layer height : I've been working with 1.6mm, but I presume 0.2 will work.
Bottom layers : 5
Temp : I'm finding 215C to work. Cooler and the inner bit hole slits don't fully seal and end up loose
Speed : Keeping it slow, around 50-60mm/s
Check for a 'Remove Holes' option in your slicer if the vent holes don't appear.

Technical notes

I've tested slicing on Cura and Creality Print. Cure seems more robust, but Creality can handle most cases.

In particular Creality Print struggled with the larger holders (e.g. 1x13) and needed two entry slits instead of one before the spiral mode would slice properly. Required some reworking to accommodate. Similar Creality needed a slit width of 0.1mm, whereas Cura could handle 0.09.

Why not 4 or more rows?
I couldn't really see a neat way to layout out 4 rows for all numbers of bits. 12 bits? 10? Easy. But 11 or 13? They just look awkward.
As for more rows, you'll star running into issues with the slits linking the various holes weakening the grip on the middle bits (an issue the inspiration for this project had, running a slit along the whole row)

2025-06-02 Update: I moved from building the body of the holder directly with 3D objects to creating a 2D shape that is extruded. Makes the rendering of the piece much quicker.