How machines work
Gears, levers, axles, differentials and more: 49 engineering ideas explained in a few simple sentences, each with an experiment to try and the builds that show it in action.
- 📏 Beams & Holes: Beams are the bones of every Technic model.
- 📌 Pins: Grippy or Smooth: Pins join beams together — some hold tight, some let things swing.
- ➕ Axles: An axle is a cross-shaped rod — anything on it turns together.
- 🛞 Axles & Wheels: A wheel on an axle turns dragging into rolling.
- 🔩 Bushes & Spacers: Bushes stop things sliding off an axle.
- 🔲 Frames: A frame is a ready-made strong rectangle.
- ⚙️ Gears: Gears are wheels with teeth that push each other round.
- 🔄 Idler Gears & Direction: A gear in the middle flips the direction back.
- 🏎️ Gear Ratio: Fast or Slow: A big gear turning a small gear makes it spin faster.
- 🔺 Triangles Are Strong: A triangle cannot be squished — a square can.
- ⚖️ Centre of Gravity: Keep the heavy stuff low and in the middle and your model won't tip.
- ⏱️ Pendulum: A swinging weight keeps steady time.
- 💪 Torque vs Speed: Slower gears are stronger gears.
- ⚖️ Levers: A bar on a pivot multiplies your push.
- 🧽 Friction: Friction is the rubbing force that slows things down.
- 🌀 Flywheel: A heavy spinning wheel stores energy.
- 🔥 Crank & Slider: A turning crank pushes a rod back and forth.
- 🔋 Stored Energy: Energy can be saved up in a spring and let out later.
- ✖️ Compound Gears: Two gear stages in a row multiply their ratios.
- ⚙️ Gearbox: A box of gear pairs where you choose which pair works.
- ↔️ Steering: Turning the front wheels makes a car follow a curve.
- 🔧 Mounting a Motor: A motor must be pinned tight, or it spins itself instead of your wheels.
- 🧭 Rack & Pinion Steering: A gear rolling on a straight rack slides it sideways.
- 🦿 Linkages: Beams joined by pins change one motion into another.
- 🛠️ Ratchet & Pawl: Lets something turn one way but not the other.
- 🥁 Cams: A bumpy wheel that lifts a follower up and down.
- 🧱 Counterweight: A weight on the other side of a pivot that balances a load.
- 🐛 Worm Gear: The Lock: A worm gear turns a gear super slowly — and never slips back.
- ↪️ Bevel Gears: Around the Corner: Slanted gears send spinning power around a corner.
- 🔗 Drive Train: The chain of parts that carries power from the motor to the wheels.
- 🐾 Four-Wheel Drive: Power goes to both axles so all four wheels push.
- 🔀 The Differential: Lets the two driven wheels spin at different speeds in a turn.
- ⚡ Electric Circuits: Electricity flows from the battery, through the motor, and back.
- 🔃 Switching Direction: Flip which way electricity flows and the motor spins backwards.
- 🔌 Plugging In: Power Functions: Battery box → (switch or receiver) → motor. Plugs stack like bricks.
- 🎠 Turntables: A turntable lets a whole model spin round.
- 📐 Ackermann Steering: The inside wheel turns more than the outside wheel.
- 🪢 Pulleys & Belts: Wheels joined by a belt pass motion over a distance.
- 🔗 Clutch & Driving Ring: A part that connects or disconnects a gear from its axle.
- ⏯️ Geneva Drive: Turns smooth spinning into step-pause-step.
- 🦘 Suspension & Springs: Springs let wheels bounce over bumps while the body stays calm.
- 📡 Remote Control: Invisible light carries your commands to the model.
- 🚜 Tracks vs Wheels: Tracks spread the weight and grip rough ground.
- ↩️ Reverse Gear: An extra idler gear flips the direction.
- 🎯 Servo Motor: A motor that turns to an angle and holds it.
- 🔒 Differential Lock: Forces both wheels to turn together.
- 🌍 Sun & Planet Gears: Gears that orbit around another gear.
- 🕰️ Escapement: Lets a clock move one tooth per swing.
- 🔀 Universal Joint: Passes turning power around a bend.