Thresher V2
A spinning thresher assembly pushes balls up a 11x11 rack gear ramp This was my 2nd attempt at building a mechanism of...
GBC Module Catalog
The most comprehensive listing of Great Ball Contraption modules
Recently Updated Modules
Studless Hoecken Linkage
This is a Studless Technic build of the mechanism from Lawrie George's Brickworld 2024 Workshop Module. The only...
Where we're going we don't need roads (aka BTTF Launcher)
This is a ball acceleration module that launches balls up a ramp under the flying Delorean (Lego Speed Champions 77256)...
Rattle Return
Rattle Return is a tall conveyor module with attachable return ramp designed to act as the return path for balls in...
Inline Shared Power Ball Bin Stepper
My own version of a typical ball bin stepper especially built for my inline shared power system. Not a classical mod of...
Inline Shared Power Tri-Wheel
A simple ThreeBladePropellerWheel Module for my Inline Shared Power System. Comes in two variants turning clock and...
Ball Dozer
Queen Watevra’s Magical Ball Mover
Tales of Space
RFID Ball Tracker
Uses modified balls embedded with an RFID tag to track loop travel times in a layout.
Perpetual Motion
Little Black Stepper
About the Great Ball Catalog
Great Ball Contraptions (GBC) modules are custom-built LEGO machines that transport small LEGO balls through creative mechanisms.
This catalog is the world’s most comprehensive resource for GBC modules, featuring hundreds of modules from dozens of builders, a lot of them with build instructions. Whether you’re a seasoned builder or just discovering the hobby, you’ll find hundreds of unique designs to explore and build.
Start browsing to discover the amazing variety and ingenuity of the global GBC community.