Lego GBC Compact Carden Lift is a module I designed for the BrickFair Virginia 2019BrickFair NJ 2019, and BrickFair AL 2020 GBC Workshops.

It is based around the Cardan Mechanism and uses an 8 and 16 Tooth gears to achive the primary relationship.

The cardan-gear mechanism invented by Girolamo Cardano in the 16th century is used to convert rotation motion to reciprocating linear motion without using linkages or slideways.

The module was designed from August 2018 through to Febuary 2019 when the parts were ordered, final box and instruction designs were worked on from April to June 2019 with the completed kits being tirelessly assembled by Stuart.

100 kits were sold at BrickFair Virginia 2019 with over 30 of them making there way onto the table for the GBC loop.

Special thanks go to Todd Webb, Stuart Roll and Tom Atkinson for the opportunity as well as KC Ross and Brian Bell for testing and sugesstions.

Night Lighting

I haven’t set this module up for nighttime running but it would certainly be possible using my custom Lego UV/Led lights or something similar.


Running video.

My unboxing and assembly video.

Assembled Kits can be seen througgout the Beyond the Brick Video for BrickFair Virginia 2019.

Early Prototype


Designing this module took an iterative approach with each major set of changes being recorded and released to testers.


Pieces Cost Difficulty
316 $$ Easy-Moderate

The instructions can be found here: Lego GBC Compact Cardan Lift Instructions.

  • Further instruction refinement to make the steps where timing occurs easier to understand.
  • Addtional slope near motor to help clear balls.
  • Addtional bracing around Cardan Mechanism to improve performance.


Pieces Cost Difficulty
308 $$ Easy-Moderate

This is the version produced for the  BrickFair VA 2019BrickFair NJ 2019BrickFair AL 2020, and BrickFair NC 2020 GBC Workshops.

The instructions can be found here: Lego GBC Compact Cardan Lift Instructions.

  • Instruction refinement to make them apply to the four production colors of Red, Yellow, Green and Blue.
  • Box Refinement.
  • Determine possible re-colors.
  • Add barcode easter egg.


  • Swap 11 axle for a 12 as it is a more common size
  • Swap gate to use more common parts
  • Use a bracket instead of a brick to hold 1×2 slope
  • Raise the window back to the top of the bin
  • Increase the height of the tiles for aesthetics and to bring to input to exactly 10 bricks tall
  • Add brace to gearbox to stop it from separating


  • Reduce brick variation to make it easier to customize color
  • Restore tile covering slot as it caused a weakness where 1×1 bricks would separate over time
  • Flip 3×5 liftarm so it no longer jams on top
  • Add 1×2 bricks to support the 3×5 lift arm better (matters more after module has worn in)
  • Restore tile layout (remove 1×3 tile)
  • Change arm weights to reduce friction and add a slight positive angle to arm which makes the pickup easier for the mechanism
  • Add a 1×2 plate to the arm to make it tilt slightly further when the forks hit it.
  • Add a wedge to stop balls stacking and blocking output
  • Add a clutch gear to drive train
  • Add tile to prevent ball and crank jam
  • Close gap to prevent ball and crank jam
  • Add extra rail to output


  • Added an output ramp to bring balls back inline with inbox.
    • This allows 2 or more cardan lifts to be placed inline
    • Stops swing arm from fouling on next module
    • Absorbs most of the ball energy from dropping out of the fork
  • Removed ½ bushes from fork as the ramp absorbs the balls energy now
  • Updated swing arm to reduce collisions with other objects
  • Changed final axle to make timing and assembly easier
  • Reduced gear ratio to better meet 1BPS when moving 4 ball batches
  • Remove tile covering slot as 3×5 liftarm was jamming on it, causing missed pickups
  • Remove lip as motor no longer overhangs
  • Corrected several bush orientations
  • Minor color changes to reduce lot count


  • Change 10 axle to 11 to remove guesswork when positioning axle in the frame
  • Change ½ bush to 1×3 lift arm to aid with timing and reduce overswing
  • Change swing arm pins to 6 axle for easier swing-arm removal
  • Change the base plate configuration to allow for left-turns when two cardan lifts are placed together
  • Increase width of input tray so that motor sits within module
  • Instructions order changed around assembly of cardan mechanism


  • Add guide plates for correct spacing of the next module
  • Add bushes to slow the release of balls
  • Add Braces to reduce flexing
  • Added a gate to swing-arm to reduce leaking


  • Major redesign of input area to reduce timing and jamming woes
  • Change gearing to run module in correct direction


  • Isolated piston and added window to wall
  • Removed spring


First working design:

  • Used a  spring to support lift
  • Piston moved entire outer wall