← All toys
Toy Workshop · round 2A tournament on the kitchen floor

Spinning Top Arenawith riders

Spinning tops from Printables, launched with a toothed ripcord, carry a printed creature from the very first spin. Whoever’s creature stays on longest wins.

Whoour 9-year-old and his friends, Dad as the referee
Wherefloor or table, a kitchen bowl as the arena
How longa round takes a minute, a league runs over several evenings
Build~130 CZK (about €5) · ~10 h of printing · one weekend

What’s new: the game is no longer just about whose top spins longest. It’s about what rides on top, so a steady hand and the center of gravity decide the result too. Each player picks their own risk with the height of the rider’s stilt.

Launching a top with a riderSide view at the moment of launch: the top with its tip on the bottom of the bowl, a saddle cap on top holding the green Lightning Lizard on a stilt. Around the pinion sits a launcher with a side slot, with a toothed ripcord coming in from the right. An arrow shows that after the pull the launcher slides away horizontally in the direction of the pull.
  1. 1Rider: a creature up to 30 mm and 3–6 g on a 0, 5 or 10 mm stilt
  2. 2Saddle cap: Ø 11 post (3–4 mm longer, per the jury), 45° cone, Ø 30 saucer with a 1.5 mm dimple
  3. 3Launcher 1749722 with a side exit (remix); the slot faces away from the pull
  4. 4PETG ripcord, a toothed rack; pulled to the right
  5. 5stlDenise top 1698197, parts with a left-hand thread
  6. 6A kitchen bowl as the arena
  7. 7Full version: an ESP32-C3 referee with a countdown and a stopwatch
1

A round in the bowl: pick a stilt and pull

The stilt height changes both the multiplier and how much the creature wobbles. After the pull the launcher slides off sideways, and the top keeps spinning with the creature on board. A league has three rounds, and you pick the stilt before each one. The round runs at 4× speed, and sound only plays after you click.

Rider time0.0 s
Multiplier×1.5
Round points–

Round 1 of 3

The 9-year-old has put the lizard in the saddle. The top stands on its tip at the bottom of the bowl.

RoundStiltTimeBonusPoints
League total0

A demo model, not a measurement. According to comments on model 1698197, the top spins for ~40 s without a rider. The saddle cap and the rider shorten that (by 10% here); the first real measurement will give the actual number. By the jury’s estimate, a rider with its center of gravity 8 mm above the foot stays on up to a tilt of about 9°. Each stilt lifts it by its own height, so the rider tips over sooner. Calibration shows the rule from the design card: the multipliers are set so that the average points come out about the same for every height.

2

The first 30 seconds and why a tenth time

The first 30 seconds

My 9-year-old sets the Lightning Lizard, on its 5 mm stilt, into the saddle on top of the spinning top. He slides the top sideways through the slot into the launcher and lowers it until the tip taps the bottom of the bowl. He pulls the ripcord, slides the launcher away, and the lizard spins along with the top. It wobbles more and more and falls off at second 38. With the ×1.5 multiplier, that makes 57 points.

Why a tenth time

Everyone picks a stilt height: a taller rider scores more but falls sooner, so it’s risk against reward. Kids invent or download creatures and collect them, parts from the MEGA collection of tops can be mixed and matched, and the league shows which combination lasts longest with which creature. A second mode, Landing, adds a skill challenge.

3

How to get a rider on the top from the launch

With the original launchers, the head of the top sits inside the launcher at launch, so a rider has nowhere to sit. The Smith (the AI agent that reworked the round-one toys into cheap builds) measured the downloaded STLs: the stlDenise launcher’s Ø 12 mm hole is closed at the top, and on 1749722 only a rider narrower than 8 mm would fit through the 8 × 15 mm window. The fix is a remix of 1749722 that slides off sideways after the pull.

  1. The Ø 12 mm hole is opened all the way through from the top. The 8 × 15 mm window is widened into a through hole.
  2. A 14 mm wide slot is cut from the hole to the side edge, on the opposite side from where the ripcord is pulled. The tangential force from the rack pushes the pinion in the direction of the pull, so into solid wall. The revised card said “on the insertion side”; according to the jury, that only holds when the ripcord runs all the way through the channel (reasoned from geometry, not tested).
  3. The head of the top gets a saddle cap: a Ø 11 mm post, a hollow 45° cone that prints without supports, and a Ø 30 mm saucer with a ~10° funnel leading into a Ø 12 × 1.5 mm dimple. The cap weighs ~3 g. The card assumes a 5–6 mm post and the saucer 1–2 mm above the plate. The jury recommends a post 3–4 mm longer, for 4–5 mm of vertical clearance, so the plate doesn’t hit the saucer as it slides off.
  4. Loading: the top, saucer and all, slides into the launcher sideways through the slot, since the Ø 10 pinion, the Ø 11.5 collar and the Ø 11 post all fit through it. Loading from below, as with the original, doesn’t work with a Ø 30 saucer.
  5. Launch: the rider sits in the dimple and the tip stands on the bottom of the bowl. One hand holds the launcher so the pinion stays engaged, the other pulls. Then the launcher slides smoothly away, horizontally in the direction of the pull, the post exits through the slot, and the saucer with its rider passes over the plate.
SolutionVerdictWhy
Through hole, just opened at the topnoOnce released, the top drops through the plate, and the rider would have to pass through a Ø 12 mm hole.
Drive on the rim, rider inside a ringnot for the minimal versionA ring gear with a ~22 mm radius instead of ~4 mm gives about five times lower RPM and ~1/30 of the energy from the same pull. Only a gear train of our own design could make up for that.
Spin-up from below, pinion near the tipnoBefore the pull the top stands on its tip alone. With 1 mm of play it tilts by about 11°, and the rider falls off before the launch.
Side exit and launch from the flooryesThe pinion stays where it is and the launcher slides off horizontally after the pull, so it never passes over the rider.
4

Rules

Mode A: rider from the launch

The rider is seated before the launch. The clock runs from the moment the launcher slides away until the rider falls off or the top stops spinning. Points are seconds times the stilt multiplier.

0 mm ×15 mm ×1.510 mm ×2to the end +10

Keep your rider on until the top stops and you get +10 points. The dimple has a fixed depth of 1.5 mm; difficulty is set by the stilt height alone.

Calibrating the multipliers

Before printing the whole set: three rides per height with a single top. The multipliers are set so that the average points come out similar for every height, which makes choosing a height a pure bet. If the heights barely differ, a 15 mm stilt gets added.

Mode B: Landing

Once the top has settled in the middle of the bowl, the rider is released from a dropper no more than 5 mm above the saucer. The funnel guides its foot into the dimple. Mode B has its own record table.

Duel and league

Duel: two tops in the bowl. If your rider falls off or your top gets knocked out of the bowl, you lose the round, even if it’s still spinning.

League: three rounds, points added up. You pick the stilt before each round, so there’s strategy to it.

Our 6-year-old’s rider: decided

A rider up to 30 mm is a small part: the small-parts test cylinder measures Ø 31.7 × 57.2 mm, and anything that fits inside it in any position fails. So the Smith proposes a big rider on a Ø 38 × 2 mm PETG base with a neck of at least 6 mm. The disc doesn’t fit into the cylinder, and when it tilts, the rim of the base rests on the Ø 30 mm saucer, so the rider hardly ever falls off. That’s a built-in handicap. If the creature snaps off its base, the broken piece is a small part, which is why she plays under supervision.

  1. Chosen: our daughter plays with the big rider, under supervision.
  2. Not chosen: she only launches and keeps time, and riders are for her big brother only.
  3. Not chosen: dropping her mode.
5

The Printables set and the creatures

In summer 2026, Printables and Open Sauce ran the “3D Printed Spinning Battle Top” contest. The reference top by stlDenise sets shared rules: fully printed in plastic, a ripcord of at most 273 mm, the blade 25 mm above the ground and at most 91 mm across. That’s why parts from different designers work together.

ModelLicenseDownloads / makesWhat the comments sayRole
1698197 Spinning Battle Tops (stlDenise)CC-BY-NC-SA328 / 9“Prints well”, ~40 s of spin with the basic design; in PETG the teeth on the top bent, in PLA “perfect”. Left-hand thread.core of the set
1749722 Modern Battle Top LauncherCC-BY-SA177 / 4“Really great launcher”, oil helped; it jams if you push the top in over the teeth. Print the ripcord in PETG.launcher (remix with a side exit)
1749046 MEGA CollectionCC-BY-SA192 / 4In PLA “printed really splendid”; a dad who ran a tournament with his kids would prefer a center screw. Parts are split in the slicer.variations: 24 tops, 47 discs, 8 tips
1638345 Pull Start LauncherCC-BY-NC496 / 3In PETG “works very, very well”; one maker scaled the rack to about 95% in Z.backup, its own system
1750350, 1769320, 77930various147 / 2 · 71 / 0 · 6,278 / 7blades fell out · no makes · needs screws and the original launchernot chosen
Arenas 1183606 (OpenSCAD, BOSL2), 1761760, 1748376CC-BY-NC / CC-BY-SA / CC-BY81 / 0 · 7 / 0 · 63 / 0none of the arenas has a make yetminimal version: a bowl; full version: 1183606

Data from the Printables GraphQL API, 2026-09-25. All the chosen models are free for non-commercial printing at home. If shared, the remix of the top (the saddle cap) falls under CC-BY-NC-SA.

Lightning Lizard rider
Height
up to 30 mm
Weight
3–6 g, center of gravity on the axis
Stilt
5 mm (×1.5)
Record
38 s · 57 points

Sample card. The record comes from the example in the design card; the full version will log real records.

  • Fan models (Pokémon, Brawl Stars) may be downloaded from Printables for printing at home. The balancing script turns them into riders. Don’t share or sell them; the characters are protected.
  • Your own creature: a child describes it or draws it on a gene sheet and sends it to the printer with the MAKE button, a companion toy idea. Claude turns the description into parameters for the creature template (head, body, ears, tail, colors) within the 30 mm and 3–6 g limits. Code balances it and prints it in MMU colors.
  • Meshy only through a parent. The resulting model goes through the same balancing script.
  • Three rider rules, enforced by code or a kitchen scale: it weighs 3–6 g, stands no more than 30 mm tall, and its center of gravity lies on the axis. The script (the trimesh library) computes the center of gravity, shifts the body over the center of the foot, tops up the weight and cuts a flat bottom.
6

Printing, AI and electronics

Printing

Tops and ripcord from Printables, the side-exit launcher remix, the saddle cap, riders with swappable stilts and a dropper for Landing mode.

AI

Turns a child’s description into creature-template parameters: head, body, ears, tail and colors. It’s only needed to make your own creature; the game itself runs without it.

Electronics

Full version only: an ESP32-C3 referee with a “3, 2, 1, let go!” countdown and a dual stopwatch.

Model (Claude)

  • turns the creature description into template parameters
  • decides nothing about the game or the physics

Code, scale and stopwatch

  • balances the creature on the axis, enforces 30 mm and 3–6 g
  • time, multiplier and the rider’s fall decide the result
7

First playable prototype

Two stlDenise tops with saddle caps, one 1749722 launcher modified in OpenSCAD (a through hole and a 14 mm side slot), a PETG ripcord, two riders with 0 / 5 / 10 mm stilts and a dropper for Landing mode. A drop of oil in the launcher hole, as its designer recommends. The top goes into the launcher sideways through the slot. Step one is a single test launch with a rider, to check that the launcher slides off without hitting the stem or the saucer. It plays without a Mac or a network.

~180 g of filament~10 h of printing~130 CZK (about €5)one weekend
PartFilamentPrint timeCZK (0.7 CZK/g, estimate)
2 tops (1698197)~100 g~4 h~70
2 saddle caps~6 g~40 min~4
Modified launcher and ripcord~50 g~3 h~35
2 riders and 6 stilts~14 g~2 h~10
Dropper~10 g~30 min~7
Silicone oilalready at home, otherwise ~100 CZK (estimate)0
Total (design card)~180 g~10 h~130

The big rider for our 6-year-old adds ~10 g, so ~7 CZK.

Full version

  • ESP32-C3 referee (~280 CZK, about €10): ESP32-C3 148 CZK (LaskaKit), 2 big buttons ~60 CZK (estimate), TM1637 display 34 CZK (LaskaKit), piezo ~10 CZK and filament ~30 CZK.
  • An arena from the parametric OpenSCAD model 1183606: ~600 g ≈ 420 CZK (about €15) and ~12 h of printing (estimate).
  • Creature cards with measured records.
  • Hex saddles with a drive lug, so the rider spins up right at launch (to be tested against the round dimple).
!

Safety and what to watch out for

The rider is a small part

A creature up to 30 mm fits inside the small-parts test cylinder, so for our 6-year-old it counts as a small part. The round-5 design card wrongly marked it as safe. So I decided: she gets the big rider on a Ø 38 mm base and plays with it under supervision.

Jury round 5 and the revised design

The floor launch is untested

Between the 14 mm slot and the Ø 11 mm post there is 1.25–1.5 mm to spare on each side. If the spinning stem scrapes the edge, the top takes a knock. The slot edges will be chamfered, and the first test launch will show whether that’s enough. The launch is delicate, too: one hand holds the launcher so the tip stands on the bottom of the bowl and the pinion stays engaged, while the other pulls and then slides the launcher smoothly away.

The revised design and the jury’s review of the revised card

The slot goes opposite the pull

The revised card put the slot on the side the ripcord is inserted from. When the ripcord is pulled back out the same side, the tangential force from the rack pushes the pinion straight into the slot, and the top slips out mid-pull. So the slot belongs on the side opposite to where the ripcord is pulled; the “insertion side” rule only holds when the ripcord runs all the way through the channel.

The jury’s review of the revised card

Vertical clearance above the plate

With the saucer 1–2 mm above the launcher, lifting the launcher by 2 mm while sliding it off is enough for the plate to hit the saucer and its rider from below. The jury recommends a post 3–4 mm longer, for 4–5 mm of clearance. The first measurement, which the card already plans, will show whether the higher center of gravity shortens the spin.

The jury’s review of the revised card

Estimates the first print will measure

The post length is an estimate, because the assembly was never put together. The first print of 1749722 will show which way its ripcord pulls, and the slot goes opposite to that. Friction in the dimple takes on the order of seconds to spin the rider up (estimate, not measured).

The revised design and the jury’s review of the revised card

The rider shortens the spin

The saddle cap and the rider add mass up top, so the top spins for a shorter time. To measure: the same top without the cap, with the cap and with the rider, three times each.

Design card

The rider physics still needs testing

In round 5 the jury pointed out that a dimple with the same radius as the foot is a ball joint, and its depth doesn’t control tipping over. So the revised design sets the difficulty through the stilt height instead, but that too is still waiting for calibration rides.

Jury round 5

Mesh check and few makes

The check gate for downloaded models in my 3D-printing workspace flagged both parts of the stlDenise top as FAIL (non-manifold mesh, 79 mm² printed in mid-air near the bottom). PrusaSlicer usually fixes that, but it needs checking. The chosen models have only 9 and 4 makes, so this is more of a set with promising early feedback.

The revised design and jury round 5
★

Jury scores

“A strong game loop (the saddle as a bet, collecting creatures, the league) for ~130 CZK. But the rider physics, meaning landing on a spinning top and staying in a round dimple, is untested so far, and the dimple probably doesn’t control difficulty the way the card assumes.”Jury, round 5. Scored before the revised design, which moved the difficulty to stilt height and put the rider on the top from the launch. Reviewing the revised design, the jury kept the total at 20 and added three catches: the slot opposite the pull, sideways loading and more vertical clearance. If the first test launch works, Build goes up to 4 and the total to 21.

“This toy drops from 22 to 20. The uncertain rider physics pulls Build down (4 → 3), and landing the rider pulls the first 30 seconds down (5 → 4). The game loop, on the other hand, is stronger (tenth time 4 → 5).”Jury, round 5, compared with round 4