My parts

Every beam, pin, axle, gear and motor in the kits, with 3D views and a motor mounting guide.

Our reference collection combines three kits. Check your build’s parts list before buying; compatible pieces you already own may work.

The Amazon links below are affiliate links. As an Amazon Associate I earn from qualifying purchases.

The reference kits

AIMATRIX 32PCS Power Functions Motors Set: Motors, battery boxes, lights, IR receiver and remote — the parts that make models move by themselves. Compare on Amazon ↗
SEEMEY 844Pcs Pins-Gears-Axles Set: Gears (incl. clutch gears and a gear shifter), knob wheels, pins, axles, connectors, an H frame, wheels, tracks and shock absorbers. Compare on Amazon ↗
ASTEM 413-piece Building Parts Group: Studless beams, bent liftarms, open frames, wheels, pull-back motors and pins. Compare on Amazon ↗

Optional supplies for STEM projects

Alternatives and extras for specific activities. Check the actual bill of materials and manufacturer’s safety guidance; no alternative is guaranteed to supply every build.

Cobers 852 pcs parts set: A large mixed assortment to compare for group activities. Audit one kit before buying multiples. An alternative collection, not an exact replacement for all three reference boxes. Audit the build bill of materials first. Compare on Amazon ↗
AIMATRIX 899 pcs gears & tracks set: Alternative big box with differentials and track links. An alternative collection, not an exact replacement for all three reference boxes. Audit the build bill of materials first. Compare on Amazon ↗
SEEMEY 184 pcs gear & axle set: A compact assortment for simple gear and axle experiments. Best for a small parts collection. A 184-piece assortment does not supply every part for every MightyCog build. Compare on Amazon ↗
TEESE 184 pcs beams, gears & wheels: Starter box that includes wheels and tyres. Best for a small parts collection. A 184-piece assortment does not supply every part for every MightyCog build. Compare on Amazon ↗
SEEMEY 32 pcs motor set: A motor and receiver collection. Compare the included motor types and connector system with your project. Compare connectors, motors, receiver and battery boxes with the guide. We have not verified these alternatives against every build. Compare on Amazon ↗
Cobers 44 pcs motor set: Motors, speed remote, AA/AAA battery boxes, lights. Compare connectors, motors, receiver and battery boxes with the guide. We have not verified these alternatives against every build. Compare on Amazon ↗
TTLYHEK 378 pcs track system: A 378-piece track system assortment. Check the link dimensions and required track length. Check wheel, tyre or track dimensions and axle fit; changing sizes can change ground clearance and gearing. Compare on Amazon ↗
TZBTSTEAM 8 pcs wheel & tyre set: Eight wheel and tyre pieces: 62 × 20 mm tyres and 43.2 × 18 mm rims. Check the listing’s selected variant. Check wheel, tyre or track dimensions and axle fit; changing sizes can change ground clearance and gearing. Compare on Amazon ↗
Cobers 21 pcs pneumatic kit: Pumps, cylinders, switch, air tank and tube. For pneumatic STEM activities. Check cylinder, valve and tube contents; these do not substitute for electric motors. Compare on Amazon ↗
ASTEM 33 pcs pneumatic kit: Larger pneumatic kit with more cylinders. For pneumatic STEM activities. Check cylinder, valve and tube contents; these do not substitute for electric motors. Compare on Amazon ↗
Yahboom micro:bit building-block robot kit: Includes the micro:bit V2, brick-compatible motor, servo and sensors. For coding activities. Confirm board inclusion, cables and power requirements before ordering. Compare on Amazon ↗
ELECFREAKS micro:bit Wonder sensor kit: Sensors and brick-compatible mounts (micro:bit sold separately). For coding activities. Confirm board inclusion, cables and power requirements before ordering. Compare on Amazon ↗
Sci-Supply 10 N spring scale: Measure pulling force in newtons. Choose a force range suitable for the activity; do not exceed the instrument rating. Compare on Amazon ↗
Newton meter 4-piece set: Four 1 N force meters for gentle-force experiments. Use a higher-range instrument for heavier loads. Choose a force range suitable for the activity; do not exceed the instrument rating. Compare on Amazon ↗
Cobers 32-piece Power Function motor kit: Another 32-piece motor collection to compare for powered projects. It is an alternative to the original reference motor box. Compare connectors, motors, receiver and battery boxes with the guide. We have not verified these alternatives against every build. Compare on Amazon ↗

Beam 3: A short strong beam with 3 holes — perfect for small joints.
Beam 5: A 5-hole beam. The most useful size for little models.
Beam 7: A long strong stick with 7 holes. Great for car sides.
Beam 9: A 9-hole beam for longer chassis rails.
Beam 11: An 11-hole beam — long enough for a whole buggy side.
Beam 13: A 13-hole beam for big frames and cranes.
Beam 15: The longest beam: 15 holes! Makes truck and racer chassis.
L-beam 3×5: A beam bent like the letter L. Makes perfect square corners.
L-beam 2×4: A small L-shaped beam for little corners and hooks.
Boomerang beam 3×7: A beam with a gentle bend, like a boomerang. Great for triangles and cool shapes.
Thin beam 2: A skinny 2-hole beam — half as thick, great for tight spaces and levers.
Thin beam 3: A skinny 3-hole beam — half as thick, great for tight spaces and levers.
Thin beam 4: A skinny 4-hole beam — half as thick, great for tight spaces and levers.
Open frame 5×7: A ready-made rectangle of holes. Super strong — it never wobbles!
Open frame 5×11: A big rectangle frame — a great base, deck or roll cage.
H frame 7×11: A giant H-shaped chassis — two long rails joined by two cross bars. The backbone of a big car!
Black pin (grippy): Joins two beams so they hold tight and do not flop around.
Grey pin (smooth): Joins two beams but lets them swing freely — for hinges and moving arms.
Blue long pin: An extra-long pin that goes through THREE layers of beams.
Red axle-pin: Half pin, half axle: plugs a round hole into a cross hole.
Tan axle-pin: A smooth axle-pin — the pin end spins freely.
Bush: A little stopper that keeps wheels and gears from sliding off an axle.
Half bush: A thin stopper — also a tiny spacer so wheels do not rub.
Axle 2: A cross-shaped rod 2 holes long. Wheels and gears grip it and spin with it.
Axle 3: A cross-shaped rod 3 holes long. Wheels and gears grip it and spin with it.
Axle 4: A cross-shaped rod 4 holes long. Wheels and gears grip it and spin with it.
Axle 5: A cross-shaped rod 5 holes long. Wheels and gears grip it and spin with it.
Axle 6: A cross-shaped rod 6 holes long. Wheels and gears grip it and spin with it.
Axle 7: A cross-shaped rod 7 holes long. Wheels and gears grip it and spin with it.
Axle 8: A cross-shaped rod 8 holes long. Wheels and gears grip it and spin with it.
Axle 9: A cross-shaped rod 9 holes long. Wheels and gears grip it and spin with it.
Axle 10: A cross-shaped rod 10 holes long. Wheels and gears grip it and spin with it.
Axle 11: A cross-shaped rod 11 holes long. Wheels and gears grip it and spin with it.
Axle 12: A cross-shaped rod 12 holes long. Wheels and gears grip it and spin with it.
Cross block: Joins an axle and a pin at a right angle — for turning corners in a build.
Double cross block: A three-hole block with holes pointing two ways.
Axle-hole connector: A pin connector with a cross hole on the side.
Axle joiner: Joins two axles end to end to make one long axle.
Angle connector: A little block that holds the end of an axle.
Pin joiner: A round tube that joins two pins end to end.
Long pin-axle block: Two pin holes at the ends and a cross hole in the middle pointing the other way.
Split pin block: A cross hole in the middle and two pin holes pointing sideways — joins an axle to two beams.
Pin-axle block: A little block with a pin hole and a cross hole at right angles.
H connector: Shaped like the letter H with four built-in pins — clicks two flat beams together.
Bent pin connector: An L-shaped corner with four built-in pins and an axle hole — great for wheel hubs and steering.
Ball pin: A pin with a ball on the end — for wobbly joints like a trailer hitch.
Ball axle: An axle end with a ball — makes a ball joint that can swing every way.
Steering arm: Holds a front wheel and swings left and right so the car can turn.
Universal joint: A bendy joint that passes spinning power around a bend.
Tiny gear (8 teeth): The smallest gear. It spins super fast when a big gear turns it.
Corner gear (12 teeth): A slanted gear that can turn power around a corner.
Grey corner gear (12 teeth): A slanted gear that can turn power around a corner.
Double-bevel gear (12 teeth): Works straight AND around corners.
Dark double-bevel gear (12 teeth): Works straight AND around corners.
Tan double-bevel gear (12 teeth): Works straight AND around corners.
Small gear (16 teeth): A small gear, twice the size of the tiny one.
Clutch gear (16 teeth): Its round middle spins freely on the axle — until a driving ring locks it. The secret of gearboxes!
Corner gear (20 teeth): A bigger slanted gear for turning power around corners.
Grey corner gear (20 teeth): A bigger slanted gear for turning power around corners.
Double-bevel gear (20 teeth): A medium gear that meshes straight or at right angles.
Medium gear (24 teeth): The classic gear. Three times as many teeth as the tiny gear.
Dark medium gear (24 teeth): The classic gear. Three times as many teeth as the tiny gear.
Tan medium gear (24 teeth): The classic gear. Three times as many teeth as the tiny gear.
Clutch gear (24 teeth): A 24-tooth gear with a round middle: it spins freely on its axle until a driving ring grabs it.
Big gear (36 teeth): A big gear — slows things down and makes them strong.
Giant gear (40 teeth): The biggest gear! Five times bigger than the tiny one.
Dark giant gear (40 teeth): The biggest gear! Five times bigger than the tiny one.
Tan giant gear (40 teeth): The biggest gear! Five times bigger than the tiny one.
Worm gear: A screw-shaped gear. Turns a gear really slowly and never slips backwards.
Gear rack: A straight row of teeth. A gear rolling on it slides it sideways — like steering!
Tan gear rack: A straight row of teeth. Put two end to end for a longer slide.
Steering rack: A long rack with a pin hole at each end — hook the steering arms on and a small gear steers the car.
Worm gear box: A round box that holds a worm gear, with a window where a gear can bite into it.
Driving ring: Slides along its axle and locks a clutch gear to it — this is how a gearbox changes gear. Comes with the shifters.
Gear shifter: A lever that pushes the driving ring left or right: flick it to change gear!
Knob wheel: A chunky 4-knob wheel. Two of them turn each other straight on OR around a corner.
Tan knob wheel: A chunky 4-knob wheel. Two of them turn each other straight on OR around a corner.
Belt wheel: A wheel with a groove round the edge for a rubber band — a stretchy belt drive.
Turntable: A spinning plate. Put a crane or a turret on top and it can turn all the way round.
Differential: A clever gear box that lets the two back wheels spin at different speeds in a turn.
Small white wheel: A small rolly wheel with a knobbly tyre — the ones that go on the pull-back motors.
Thin-tyre wheel: A slim grey wheel with a thin black tyre — light and fast.
Yellow-hub wheel: A medium chunky wheel with a yellow middle.
Big tyre wheel: A big bouncy wheel for trucks and racers.
Train wheel: A little wheel for wagons and trains.
Track wheel: A toothed wheel that grabs the track and pulls it round.
Small track wheel: A smaller track wheel for idlers and small tanks.
Track link: Snap lots of these together to make a caterpillar track.
Grey track link: More track links, in grey (and some in other colours).
Big track link: A bigger, grippier track link for the big track wheels.
Wide track pad: A wide track pad — makes a tank track as wide as a hand.
Suspension arm: A swinging arm that holds a wheel and lets it bounce up and down with a spring.
Hand crank: Put it on an axle and wind the handle round and round to power your machine by hand.
Soft spring: A springy shock absorber — squish it and it bounces back.
Hard spring: A stiffer shock absorber for heavy loads.
Pull-back motor: Pull it backwards, let go, and it zooms forwards! A spring inside stores the energy. Two round holes at the top and a cross at the bottom go right through it.
AA battery box: Holds 6 AA batteries and sends power to motors. The orange switch picks forward, stop or backward.
AAA battery box: A smaller battery box for AAA batteries. It has studs like a big brick, a green on button and an orange direction switch.
LED lights: Two tiny lights on a wire — headlights for your car!
Extension wire: Makes a motor wire longer so it can reach the battery box.
Train motor: A motor bogie for trains: two axles with train wheels, and a round bump that clicks under a train base.
M motor: A medium motor — fast and light. Great for cars and fans.
L motor: A large motor — about as fast as the M motor but much stronger.
XL motor: The strongest motor! Slow and super powerful — for cranes, winches and heavy trucks.
Servo motor: A motor that turns to a position and stays there — made for steering. Its axle can go right through it.
Direction switch: Flip the lever to make a motor go forwards, stop, or backwards.
IR receiver: Listens for invisible light signals from the remote and drives two motors (red and blue).
Speed remote: The remote control! Two dials set the speed of each motor.