This is a knob cap that fits M4 Allen (aka Hex or Inbus) socket cap screws and turns them into a knurled thumbscrew. The internal hexagonal driver in the knob turns the screw the same way your Allen wrench would, while the knurled surface of the bigger knob gives your fingers something to hold on to.
This works remarkably well, but always remember that you're working with 3D-printed plastic. Don't expect wonders and don't use excessive force tightening the screws.
You can find my blog about this design here: https://style.oversubstance.net/2020/02/m4-hex-socket-thumbscrew-knob-caps/
I designed this for my Goodman ZONE 3D-printed camera, which uses 4 M4x20 Allen socket cap screws to mount the lens. Mounting a different lens requires a 3mm Allen wrench to remove the screws. I designed these caps to fit into the Allen socket and convert them to knurled thumbscrews, allowing me to switch lenses on-the-go without an Allen wrench.
I followed the DIN 912 M4 standard: 7mm head diameter, 4mm head height, 3mm hexagonal driver. The knob is 0.5mm shorter than the head, so it will not damage the surface of an object your screw it into.
| m4-allen-socket-thumb-screw-cap.stl | 214.2KB |
