Giant Euler's Disk | Machining + Test

Machining and testing out our new giant Euler's disc physics educational toy.

[Bear]

There's actually a mathematically optimal ratio of thickness to diameter (t:D = 1:6) for the maximum initial sum of angular momentums. (Leonhard Euler was the physicist/mathematician that defined and figured it out)
I would recommend cutting a smaller diameter to a greater thickness to still get to the same/similar weight.
With a slightly concave mirror polish and a minimal radius (none if possible) you should get a howling banshee for at least 5 minutes (more like 25-30).

[big_whopper]

PlaDoh will absorb energy like crazy! Epoxy the plate to the concrete and you’ll really have something!

[SuperAWaC]

The spinning surface should be slightly concave so it self-centers, it can be smaller that way. I made a 3" diameter disc out of tungsten carbide, and it wobbles for a very long time.

[davdsmth]

Even the small amount of playdough under the plate will bleed off energy quickly as it compresses. A rigid tripod arrangement around the rim would be more efficient, I think. Maybe just weld three "spikes" 120 degrees apart around the circumference - to stop the plate moving laterally. The noise could be deafening though as the plate flexes...

[Destrosndone]

you really need to mirror polish them up
then they spin for ages
and the final "scream" will be better ;)

[bernardfender]

DEFINITELY MORE ENGINEERING AND LATHE STUFF PLEASE.
Timo's Triumph is the best!

[ross]

A granite slab from a monument maker could be an excellent base. They usually have damaged pieces already polished.

[tim_bbq]

I was waiting see the performance difference between the large radius corner and the small radius corner. Also could you mark it so we can see the rotational speed? I see more videos coming to explore this !

Thanks for sharing!

[BentTreeFarmPa]

I wonder how much heat was generated while that was spinning, would be cool to look at it with an infrared camera.

[johntheux]

With some surface hardening it could last even longer I think.

[FirstLast-gwmg]

I think the play-doh probably absorbs some energy, you need a hard surface to maximize the elasticity of the collision (bounce).

[alexwitteried]

The english word is in fact "concave" you nailed it.

[twestgard]

There’s lots of flex and lost energy in the bottom plate. I could even see it moving at one point

[jeromeprater]

I have an Euler's disc made from a precision ground ring of Tungsten Carbide that weighs 30 pounds (13.6 kg) and is 14 inches (35.56 cm) in diameter. I have spun it on a sliding glass door that was aligned horizontally at the four corners. The hard part is to keep it centered and to avoid breaking the glass. Some of these discs can spin more than 3 minutes.

[CameronMcCracken_Art]

Hey! I am going to try this at home with a coin and table, probably the only time it’s safe to recreate a video of yours.
You didn’t warn us not to, so that must mean it’s safe! 👍

[Dr_Petey_Wheatstraw]

Cast iron, due to the carbon precipitated between the steel grains, actually has a lot of natural damping as well. So using a steel would have even lower losses. But that natural damping is why cast iron is used for machine tool bases.

[DanielJohansson]

In case you know Swedish there is a trick to knowing the difference between concave and convex: konVEX = VÄXer på mitten, konkAV = smalnar AV på mitten.

[JosephParker_Nottheboxer]

Any chance you can re do the spin on this with some marks on the disk showing how fast its spinning? Even just pen marks would be interesting, to see how much it slows down as it's height gows down. For science right :)

[terryboyer]

I love Annis laugh. It's Pretty Good!

[xroqus]

Watch how the spin angular momentum axis parallel to the diameter revolving the disk bleeds into spin angular momentum rotating the disk. Nice! Put a mark on the narrow edge and use a tachometer to measure the spin-up.