Even the Densest Metal Doesn't Exceed USPS Shipping Weight Limit (2022)

[cbm-vic-20]

There's a fun "street science" video where a small USPS Flat Rate mailer is filled with a solid block of tungsten, challenging passers-by to pick it up.

https://www.youtube.com/watch?v=1YIDkr33sjo

[Phrenzy]

I have another thing to add to the list, "If I became a millionaire."

A complete set of tungsten dumbbells.

[elbigbad]

This is funny, with that size of fully filled with tungsten the small flat rate box must be 40-45lbs. That’s massive for something of that size and lack of carryability. The same size as the large weights for barbells at the gym.

[tgflynn]

The USPS claims to deliver large heavy packages but doesn't. I just found a note in my mailbox saying "too heavy to lift, pick it up at the loading dock". Not helpful when you're disabled and don't drive. The box is supposed to only be 40 lbs but it is large.

[brk]

We had that happen too with things that for whatever reason Amazon decides to ship via USPS.

USPS will accept the package, and bill the sender for delivery to the end point, but then just decide "nah, you come get it" once it gets to their local facility.

[Moto7451]

I’ve had good experiences with this and my local USPS. They usually send a dedicated driver in a van rather than the truck. The only failure here was a lightweight toolbox shipped from Indiana. Meanwhile I’ve had all sorts of AliExpress sourced machines sent through the mail and delivered to my doorstep.

[perihelions]

Here's the other HN thread from last year,

https://news.ycombinator.com/item?id=31116024 ("It is physically impossible to exceed the weight limit for a Small Flat Rate Box", 244 comments)

[lowestprimate]

I once got to visit a jewelry manufacturing site where to get in and out you had to go through an MRI to ensure you didn't pick any gold or platinum dust on the tour. There were pallets of gold lying on the floor worth about 200 million. We got a chance to try to pick up a bar of gold about the size of a large loaf of bread and our tour guide said, "if you can pick that up and walk it to the front door, we'll let you have it". Turns out it weighed about 200 lbs and I could not get enough of grip to move it let alone pick it up. Fun visit.

[the8472]

That's one way to enforce the No surprise black holes in a box rule.

[wunderland]

No explanation as to why USPS picked this particular weight limit?

[travisjungroth]

The 70 pound limit is for all USPS packages. It would be possible to exceed that limit for the medium or large flat rate box, or a custom box.

The weight limit has been raised and lowered over time. It was first 70 pounds in 1913 for nearby addresses and 70 pounds anywhere domestic in 1931. It was lowered in 1952, but has been 70 pounds since 1983. Source: https://about.usps.com/who/profile/history/universal-service...

That doesn’t exactly answer why. Based on that page, the answer is the same as for most things like this: a complex mix of government, commercial and logistical factors decided by committee. There doesn’t appear to be a “fun fact” answer like “most postal workers after WW2 were infantry veterans and the limit was set to be the same as a crate of ammunition”.

[blamazon]

I believe it is connected to the requirement that mail carriers regularly lift things of 70 pounds maximum weight.

A parcel heavier would therefore be a two-person lift and not conducive to the lone mail carrier model generally used for USPS last mile.

[skittlebrau]

Looks like that’s the max weight for any package.

[causi]

Possibly it's the calculated limit of some type of package-handling machinery. Maybe it's more interesting, like the original planned limit was 7kg and somebody in the editorial chain mistakenly thought the conversion rate was 10lbs/kg.