April 15, 2026
Description
My design uses a short, flexible hinge to clamp hex bits into place. Springy filaments give the best results, so regular PLA may be challenging to work with. Modified PLA filaments (like PLA Pro from Polymaker) with more flex may work better, but I have had the best success with PETG and ABS. You can find ready-to-print stl files for two sizes of bits.
I improved the parametric model for Fusion360. You should not have to rerun any operations in the timeline! I offset the second row of bits to make pulling them out a little easier. I also added models for 4 mm hex bits.
You can fine tune the fit by scaling X and Y in your slicer. Make a test print and lookup the scale factor in the tables below. You can make a tall bit holder by scaling Z.
| 1/4 inch Standard Hex Bits | |
| Which test size ? | XY scale (%) |
| -0.15 | 97.66 |
| -0.10 | 98.44 |
| -0.05 | 99.22 |
| +0.05 | 100.78 |
| +0.10 | 101.56 |
| +0.15 | 102.34 |
| 4 mm Precision Bits | |
| Which test size ? | XY scale (%) |
| -0.15 | 96.41 |
| -0.10 | 97.59 |
| -0.05 | 98.80 |
| +0.05 | 101.20 |
| +0.10 | 102.41 |
| +0.15 | 103.59 |
You can also design a completely custom bit holder with the parametric f360 file.
| Parameter | |
| Wall thickness | wall |
| Hex diameter measured from parallel sides | d |
| Height of hex clamp | bit_height |
| Length of flexible hinge | hinge |
| Number of bit holders | num |
Thanks for visiting, and enjoy!
Major update: Published revision 2 with improved CAD. Added 4 mm bit holders.
Minor update: Updated the precision test print with better labels.
License:
Creative Commons — Attribution — Noncommercial — Share Alike
9
Flying Gyroscope
