Girders and Gears is the place for fanatical hobbyists and collectors of metal construction sets. Serious enthusiasts show off what they build with their sets, and share their knowledge about building techniques, history of the sets, and how to restore the old ones. They work in every historical and contemporary construction set. Not all construction sets are toys. Heavy duty ones can be used for prototyping.
Constructor sets come in 3 categories:
Repetitive Hole Beam
Consistently space holes along the length permit modular connections.
Bitbeam - LEGO Technic-compatible building technology. Bitbeam can be printed on a 3D-printer or cut with a CNC router or laser-cutter, which means it can be made out of plastic, wood, or aluminum.
Contraptor – Make your own. Contraptor is a DIY open source construction set for experimental personal fabrication, desktop manufacturing, prototyping and bootstrapping. Not sold. Make your own, with Sketchup files.
A long slot in the beam permits a secure connection with infinite adjustment of spacing.
Makerbeam – Mini-T is a miniature version of larger T-slot building systems.
OpenBeam – Smaller version of industrial t-beam, with free plans that you can manufacture yourself or purchase.
Makeblock – Hybrid: Repetitive holes and slots. Various special shapes.
Beams and Connectors
Complicated rods — more than simple beams — slip into complicated connectors
K’Nex – Flexible rods with plastic connects allow non-grid structures.
Lego/Technic – Highly crenelated beams and smaller parts with repetitive holes plug into different shaped connectors.