What is the difference between black and grey Technic pins?
Pins join beams together — some hold tight, some let things swing. Black and blue pins have tiny ridges that grip, so the beams stay put. Grey and tan pins are smooth, so the joint can swing like a door hinge. Engineers pick the right pin for the job.
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Explore the printable packTry it yourself
Join two beams with a black pin and wiggle them. Now try a grey pin. Which one swings?
Build it: 17 builds that teach pins
🚗 Tiny Roller: Your very first rolling car — only 13 pieces! (level 1 of 5, about 5 minutes, 6 steps)- ⏱️ Pendulum Metronome: Give it a nudge: tick… tock… tick. Move the wheel to another hole and count again! (level 1 of 5, about 10 minutes, 9 steps)
- 🔀 Dual Output Gear Bench: One central input drives two unequal outputs: count each branch independently. (level 2 of 5, about 20 minutes, 14 steps)
- 📐 Crank Orbit Bench: Trace a crank pin’s circle and compare its one-axis travel at equal angle steps. (level 2 of 5, about 15 minutes, 10 steps)
- 🛒 Push Buggy: A sturdy buggy with a push bar held up by super-strong triangles. (level 2 of 5, about 15 minutes, 12 steps)
- 🛺 Pull-back Trike: A three-wheeler with a spring engine — twist the front wheel and it drives in circles! (level 2 of 5, about 20 minutes, 9 steps)
- 🦀 Lazy-Tongs Grabber: Squeeze the handles and the criss-cross arms shoot out to grab things far away! (level 2 of 5, about 20 minutes, 11 steps)
- 🎯 Spring Catapult: Cock the arm, click the trigger, FIRE! A spring flings the ammo across the room. (level 2 of 5, about 25 minutes, 14 steps)
- 🐦 Woodpecker Automaton: Turn the handle and the woodpecker pecks: tok-tok-tok-tok! (level 2 of 5, about 20 minutes, 16 steps)
- 🏎️ Steering Go-Kart: Turn the steering wheel and the front wheels really turn — just like a real car. (level 3 of 5, about 30 minutes, 25 steps)
🏗️ Worm-Gear Crane: Crank the worm gear to lift the boom — then let go. It stays up by itself! (level 3 of 5, about 30 minutes, 15 steps)- 🏰 Castle Drawbridge: Wind the handle and the heavy bridge slowly rises — and stays up when you let go. (level 2 of 5, about 30 minutes, 15 steps)
- 🛻 Bouncy Monster Truck: Four big wheels on four springy shock absorbers. Boing, boing! (level 4 of 5, about 45 minutes, 29 steps)
- 🚂 Floor Express: A remote-control locomotive with headlights, a chimney and a log wagon. (level 4 of 5, about 40 minutes, 17 steps)
- 🌀 Coasting Wheel Bench: Spin a retained tabletop wheel gently, then measure how it slows down. (level 2 of 5, about 15 minutes, 8 steps)
- ⭕ Rim Distance Bench: Two unequal wheels share one shaft: equal turns, unequal rim travel. (level 2 of 5, about 15 minutes, 9 steps)
- 🛠️ Ratchet Car Jack: Crank the handle — click, click, click — and lift a toy car. Let go and it stays up! (level 3 of 5, about 35 minutes, 15 steps)
Common engineering questions
How can I try pins at home?
Join two beams with a black pin and wiggle them. Now try a grey pin. Which one swings?
Which builds teach pins?
17 MightyCog builds teach it: Tiny Roller, Pendulum Metronome, Dual Output Gear Bench, Crank Orbit Bench and Push Buggy and more. Start with Tiny Roller: 6 steps, about 5 minutes.