What does a bush do on an axle?
Bushes stop things sliding off an axle. A bush is a little stopper that grips the axle. Put one on each side of a wheel or gear and it stays exactly where you want. A half bush makes a tiny gap so parts do not rub.
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Take the bush off one wheel and shake your car. What happens?
Build it: 16 builds that teach bushes & spacers
- ⚙️ Gear Friends: Three gears holding hands — spin one and they all dance. (level 1 of 5, about 8 minutes, 6 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)
- ⭕ Rim Distance Bench: Two unequal wheels share one shaft: equal turns, unequal rim travel. (level 2 of 5, about 15 minutes, 9 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)
- 🏎️ 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)
- 🦾 XL Power Crane: The strongest motor plus a worm gear: 24 times slower and super strong. (level 4 of 5, about 35 minutes, 27 steps)
- 🪖 RC Tank: Two motors, two tracks, one remote. Spin on the spot and climb over anything! (level 4 of 5, about 60 minutes, 27 steps)
- 🌉 Speed-Cancelling Gear Bridge: A 40–8–40 gear train: the middle turns five times, but the ends stay together. (level 2 of 5, about 15 minutes, 5 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)
🧪 Gear Speed Lab: Two cranks, two gear pairs: one makes things FAST, one makes things STRONG. (level 2 of 5, about 20 minutes, 13 steps)- 🔬 Compound Counting Bench: Two five-to-one stages multiply: count 25 input turns for one output turn. (level 2 of 5, about 20 minutes, 7 steps)
- 🔄 Reverse-to-Turn Car: Only one motor — but it can still turn! Drive backwards and the wheels swing round. (level 4 of 5, about 50 minutes, 24 steps)
- 🏆 Independent Rally Car: Every wheel on its own springy arm, a differential, universal joints and Ackermann steering. (level 5 of 5, about 90 minutes, 47 steps)
- 🌐 AWD with Central Diff: All four wheels driven, with a differential in the MIDDLE of the car — like a rally car. (level 5 of 5, about 90 minutes, 28 steps)
- 🚧 Twin-Motor Dozer: Wide caterpillar tracks, one motor per track, and a blade that cranks up with a worm gear. (level 5 of 5, about 100 minutes, 33 steps)
Common engineering questions
How can I try bushes & spacers at home?
Take the bush off one wheel and shake your car. What happens?
Which builds teach bushes & spacers?
16 MightyCog builds teach it: Gear Friends, Dual Output Gear Bench, Rim Distance Bench, Crank Orbit Bench and Push Buggy and more. Start with Gear Friends: 6 steps, about 8 minutes.