Print in place Bi-Directional Ratchet Screwdriver

Blog: https://dev.joesturge.com/p/3d-print-in-place-a-design-journey/

OnShape Files: https://cad.onshape.com/documents/5b146e263caac3060752204d/w/15bde26dc6901519c376ed2c/e/cecbda455fb1c20a8470df09

Features

• Fully print-in-place – no assembly required

• Accepts standard 6.35mm (1/4") hex bits

• Bi-directional ratchet (left / right)

• Lock position

• Surprisingly strong and usable

• Designed to print cleanly on a well-tuned printer

Print Settings

The screwdriver is carefully designed to not be too dependant on print settings, but I would recommend a layer height of 0.2mm and 15-20% infill, more if you like it to be weighty.

Optional (but highly recommended) - Use Fuzzy Skin on the flat parts of the handle to add a nice gripping surface

Important

• Tolerance matters – if your printer is not dialled in, it may fuse

• Designed with ~0.3mm clearances

• If it doesn’t move after printing insert a hex bit and force it to turn as if you are unscrewing something really sharp and fast, you should hear a crack, then you are good to go

How It Works

The ratchet mechanism is fully internal and prints in place using small clearances.

It relies on:

• angled ratchet teeth

• a sliding selector

• controlled flex in printed parts

If you’re curious about the design process (and all the failures along the way), I wrote it up here:

https://dev.joesturge.com/p/3d-print-in-place-a-design-journey/

Known Quirks

• May feel slightly “crunchy” depending on your print quality

• First movement after printing can require a bit of force

• PLA works for me, I have not tired in PETG but it should be even better with that

Tips

• Use fuzzy skin in your slicer for grip (looks great, feels better)

• If the selector is stiff, work it back and forth a few times

• If parts fuse:

  • check flow calibration

  • slightly reduce extrusion multiplier