The brutal physics of the "milk crate challenge"

Originally published at: The brutal physics of the "milk crate challenge" | Boing Boing


Great. That’s all we need. ERs full of horse paste aficionados and milk crate tumblers. Let’s toss in some murder-hornet adopters for the hat trick.


IIRC (rule of thumb) the highest stable height of a stack of non-interlocked similar items (under gravity, not with some twit trying to climb it) is five times diameter (or smallest length or width) of the base.

The column of crates is barely stable just under its own weight.

With a bit of a safety factor on it material handling practice seems to agree.

A good rule of thumb for ensuring a stable stack is to observe a height to base ratio that does not exceed 3:1 (or 4:1 at most if the stack is effectively interlocked and there is a good grip between the contacting surfaces).


It’s almost as if these “challenges” were dreamt up and seeded on social media by unscrupulous, profit-hungry medical treatment corporations.

Which, frankly, is more the sort of conspiracy theory there really ought to be more of than the current crop of fuckwittery.


Yep, it’s stupid. If younger, I would have totally ruled it. Can’t believe we never thought of that.




I don’t know about you other old folks like me, but we literally decorated our cheap apartments with crates. I’m already WELL aware of the problems with trying to stack crates and expect them to hold any amount of weight if they’re not tied together.

Benefits of growing up the 80’s.


That’s going to depend largely on the mass to size ratio of the stacked items, and the footprint of each.

If you mounted a weight in the center of each basket, as you increase each weight the column would become increasingly more resistant to tipping. So if you wanted to “win” the milk crate challenge, you could start by using the old steel milk crates, which have a lot more mass than the modern plastic ones.


Milk crate mattress base! Milk crate record album storage! Milk crate bookshelves! Etc.

ETA: Looking around, I still have one milk crate.


It’s strangely illegal to have milk crates. No idea why.

If the cops catch you with a milk crate they will arrest your ass. Not even joking.


Well aware. I"m in Tijuana though. Think they’ll extradite me? /s


I just thought that was bizarre.

And it’s a funny mental image to think of one of these TikTok kids handcuffed to their hospital bed like a dangerous fugitive for the possession of milk crates. For values of “funny” approaching “American”.


I’ve always thought this was weird. I remember seeing that written on a milk crate my dad used as a propane tank holder when I was a kid, like maybe 10 years old, probably younger. I spent far too long worrying about the fact it was illegal.


There is a part of me that is perpetually amazed and amused by the agility and balance I have as a result of skating. That part tells me that I probably could do this, under ideal circumstances, wearing my big huge duck boots and a full set of roller derby PPE. But holy shit, just no. I have a couple rules about falling, and one of them is to involve as few rigid objects as possible.

But you’re probably okay to copy them.


Having stood on a single milk crate to reach a high shelf. Unsuccessfully. I think the needs here might be a little more extreme.

Milk crates are made of pretty slick plastic. And are actually meant to slide around easily for loading and unloading from trucks. They’re light weight. And once you flip them over, very little material is actually in contact with the ground.

The only thing that makes them moderately stackable is that they interlock (loosely) when stacked.

Because they’re the property of the dairy or other company that sends them out.

They’re actually kind of brilliant. It’s just an endlessly reusable shipping container. The dairy business, and a handful of others, use them instead of cardboard boxes. But the system requires their return.

It’s like kegs, or shipping pallets.

And no, no one will arrest your ass. It’s to keep people from piling up a bunch and selling them or other dairies from cribbing your shit.

Going back to what I’m more familiar with, kegs. A common way for big companies to fuck with little breweries is to steal or misdirect their kegs. Particularly when an associated distributor drops a smaller brand they sometimes just keep the kegs in an attempt to close them out of the market.

Kegs are a significant expense and you need at least 3x as many as you intend to produce/sell in the stream to maintain supply. A chunk of them disappearing destabilizes your supply and usually costs too much to replace.

Milk crates would be less extreme. But same principal.


Not that illegal.


But are they really milk crates if they don’t have the internal dividers? Or is that a UK thing (milk crates here were/are for one pint glass bottles).


Unless they were for free school milk which iirc was in third of a pint bottles. And warm and thick. Mmmm.


Must be UK thing. Never seen that before.