October 18, 2025
Description
I reversed-engineered my broken Sigma bc1009 mechanical interface (the one providing the "Twist Lock System").
This part does not come with the actual holder that adapts to the bike's handlebar, as mine was not broken (yet).
As this part is supposed to be survive outside, being showered by UV light, you may choose a material that handles UV and ideally doesn't creep.
I chose PETG, we'll see if it survives through time!
You may find the source files (FreeCAD 1.0.2) hosted here: GitHub repository, should you need the exact measurements or to adapt the back plate to remove all the Twist Lock System mechanical footprint (like, if you want to merge the backplate with a custom bike holder, it'll be easier without the holes!)
License:
Creative Commons - Attribution - Non-Commercial - Share Alike