📦 Conveyor Belt: step-by-step build

A factory belt that carries your parts from one end to the other — and drops them in a box.

In factories, airports and supermarkets, things ride on moving belts: parcels, suitcases, even your shopping! Our belt is a long loop of track links wrapped round two track wheels. A motor turns a worm gear, the worm turns a big gear on one wheel, and the whole loop starts to crawl. Put a gear on the belt and watch it travel all the way to the end and plop into the box.

Level 3 of 5 (medium)
About 50 minutes
22 steps, 89 parts
Powered by: Motor
Series: Mechanical Wonders

What you will learn

Tracks vs Wheels: Tracks spread the weight and grip rough ground.
Worm Gear: The Lock: A worm gear turns a gear super slowly — and never slips back.
Electric Circuits: Electricity flows from the battery, through the motor, and back.
Mounting a Motor: A motor must be pinned tight, or it spins itself instead of your wheels.
Plugging In: Power Functions: Battery box → (switch or receiver) → motor. Plugs stack like bricks.

Build these first

🪖 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)
🏗️ 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)

Parts you need

5 × Open frame 5×7
18 × Black pin (grippy)
2 × Beam 15
1 × Axle 8
6 × Bush
4 × Half bush
1 × Axle 10
1 × Medium gear (24 teeth)
2 × Small track wheel
36 × Track link
1 × Beam 9
2 × Beam 7
1 × L motor
1 × Worm gear
1 × Axle 5
1 × AA battery box
2 × Red axle-pin
2 × Split pin block
2 × Blue long pin

Steps

Stand a 5×7 frame up on its short side. This is the front-left leg.
Push 2 black pins into the top row of the frame (holes 3 and 5), pointing inwards. Push a long 15-hole rail onto them by its holes 1 and 3.
Push 2 black pins through rail holes 11 and 13 and press the back-left leg frame onto them (its top-row holes 1 and 3).
Front axle: push an 8-long axle through the frame and rail hole 2, slide a bush onto it on the inside, and push a half bush onto the tip sticking out of the frame.
Back axle: push a 10-long axle through rail hole 14 and the back frame so it sticks out 3 holes outside, and slide a bush onto the inside.
On the outside end, slide on a bush, then the 24-tooth gear, then a half bush on the tip. The gear is trapped between them and cannot slide off.
Belt: hold a small track wheel and snap 9 track links together in a row under it.
Snap on 9 more links, curling them round the second track wheel.
Snap on 9 more links.
Snap on 9 more links.
Close the loop round both wheels and slide the whole belt onto the two axles from the front. Then slide a bush onto each axle in front of the track wheels, so they cannot slide off.
Push the second 15-hole rail onto the other ends of both axles.
Push 2 black pins into rail holes 1 and 3 and press the front-right leg frame onto them. The front axle goes through it too — push a half bush onto its tip so the right side can't slide off.
Push 2 black pins into rail holes 11 and 13 and press on the back-right leg frame.
Inside the back-left leg, push 2 black pins into the frame's side holes one row below the rail (first and last hole of that row). Press a 9-hole joiner beam onto them.
Push 2 black pins out through the last 2 holes of the joiner beam and press a 7-hole cradle beam onto them, sticking out behind the belt.
Push 2 black pins into the first and last hole of the cradle beam, pointing outwards. Press the L motor's upper side holes onto them, output facing the gear.
Hold the worm gear under the 24-tooth gear with a bush on its right, and push a 5-long axle through both into the motor. Put a half bush on the left tip so the worm cannot slide.
Push 2 black pins into the 4th and 5th holes of the front-left leg's left side, pointing out. Hang the AA battery box on them by the top two holes of its right flap and plug the motor onto the box.
Catch box: push red axle pins into the 2nd and 3rd holes of the front-left leg's left side, pointing in, and slide a split pin block onto each, one on top of the other.
Push two blue long pins up through the 5th and 7th holes of a long side of the red 5×7 frame, and press the frame up under the blocks so both pins go through both blocks. It is the floor of the box.
Press a 7-hole beam flat onto the other long side with two black pins as a wall.

Play time

Switch it on and put gears, bushes and pins on the belt at the back. Watch them ride to the end and drop into the box. Time how long one gear takes to travel the whole belt!

Real-world inspiration

Belt conveyor — https://en.wikipedia.org/wiki/Conveyor_belt