Mechanism guides: levers, cams, cranks and linkages
Levers, cams, cranks, linkages and clocks that seem to move by magic. Each guide explains one mechanism, lets you try it in an interactive lab and links a free build that shows it.
22 guides
- Mechanisms
How does a friction car work? Flywheel car questions answered
Why a push-and-go friction car keeps rolling: a geared-up flywheel, why it whirrs and spins backwards, and a lab built on a real Technic-style flywheel car.
- Mechanisms
How do two geared pointers help a distance cart measure farther?
Build a two-scale survey cart, decode repeating pointer readings and calibrate wheel rollout with an interactive fine-and-coarse distance challenge.
- Mechanisms
Does gear reduction make a Technic-style slider more accurate?
Build a two-stage rack positioner, trace three interacting gear stages and test small target moves, reversal take-up and real positioning uncertainty.
- Mechanisms
How a spirograph drawing machine decides how many petals it draws
The gears set the petal count before the pen touches paper. Build a Technic-style spirograph, learn the petal rule and predict flowers in a drawing lab.
- Mechanisms
How cams work: make a Technic-style machine play a drum beat
A cam is a bump on a turning shaft. Count the bumps and you can write a rhythm. How cams work, with a Technic-style drum machine and a rhythm lab.
- Mechanisms
The coin puzzle inside planetary gears: why the orrery’s Earth spins 2⅔ times
Roll a coin round an equal coin and it turns twice, not once. The same extra turn drives planetary gears, a Technic-style orrery and Watt’s beam engine.
- Mechanisms
How to work out a counterweight: balance any lifting arm with one rule
Weight × distance on one side must match the other. A step-by-step way to size and place a counterweight, tested on a Technic-style barrier gate.
- Mechanisms
Ratchet won’t hold? How a ratchet and pawl works, and how to fix one
A pawl stops a load falling back, but only after it slips up to a tooth. How ratchets work, five common faults and fixes, with Technic-style builds and a lab.
- Mechanisms
The south-pointing chariot: how an ancient cart pointed south with gears
No magnet, just a differential that counts how much further one wheel rolls. The story of the south-pointing chariot, a Technic-style rebuild and a lab.
- Mechanisms
Why does a worm gear need many turns—and stops on its own shaft?
Assemble a hand-powered worm counting bench, predict a 24:1 reduction and investigate friction without claiming every worm drive self-locks.
- Mechanisms
How do you build a pendulum that swings freely and stays together?
Build a retained Technic-style pendulum, check its bearings and bob, then compare gravity torque and measure full swings fairly.
- Mechanisms
Can equal gear moments guarantee a level see-saw?
Build a retained lever bench, predict gear-only moments and test how the pointer and beam change the real balance point.
- Mechanisms
Why does a fast middle gear leave the end speeds equal?
Assemble a retained 40–8–40 spur gear bridge, predict turns and diagnose why a 1:1 overall ratio still has friction and clearance limits.
- Mechanisms
How can one differential carrier let two shafts turn at different speeds?
Build a hand-driven differential bench, compare free and held outputs, and test the ideal average-speed rule without confusing it with measured traction.
- Mechanisms
How does an offset Technic-style slider crank change piston travel?
Build a supported twin-piston mechanism, predict its offset-slider travel and check the guides, crank and connecting rods through a full turn.
- Mechanisms
What physically stops a Technic-style escapement wheel between releases?
Build the retained pin-pallet clock, predict releases versus tick-tock cycles and inspect the physical stops without claiming calibrated timekeeping.
- Mechanisms
How can a Technic-style four-bar turn a complete crank into a rocking beam?
Build the supported pump-jack linkage, identify four pivots and test why its short crank turns fully while its long walking beam only rocks.
- Mechanisms
How can one shaft make two different cam rhythms?
Build a two-follower cam drummer, predict lifts per turn and distinguish profile, return, support and sound in a fair experiment.
- Mechanisms
What is a worm gear, and why can’t it turn backwards?
Why a worm gear holds its load when you let go, when it can slip after all, and five Technic-style builds that use the lock.
- Mechanisms
Catapult vs trebuchet: a stored-energy experiment you can aim
How a spring catapult and a counterweight trebuchet store energy, why 45° is only best in theory, and a predict-and-launch range game.
- Mechanisms
How do linkages make walking legs? Trace a foot path and build a walker
See how a turning crank and a few pinned beams draw a step: trace foot paths on screen, then build a pump jack and a walking spider.
- Mechanisms
Simple machines: 6 builds that show levers, cams and cranks
Levers, counterweights, cams and cranks explained through six hand-powered builds, from a 12-minute see-saw to a trebuchet.