
How much usage can a Lego piece take before it loses its 'clutch power'? - sonergonul
http://phillipecantin.blogspot.com/2013/02/legos-magic-number-is-37112.html
======
famousactress
My first tech job was testing software at Hewlett Packard, circa '96-97. One
of the projects I worked on was HP's first (I think) digital camera. The
hardware testing was apparently running behind due to challenges the hardware
team was having with abrasive qualities of some of the paints they'd chosen,
and one day a bunch of us were asked to go help expedite some hardware tests.

Every button, latch, and moveable part on that camera was rated to a certain
number of presses and uses. A team of folks (which for one day that winter
included myself) sat in a room pressing buttons and drawing notches on a sheet
of paper until the product failed or qualified. It was kind of eye opening,
actually. For weeks afterward I was nervous about whether the next button
press on my tv remote was the last :)

I'm curious, 16 years later.. How much of this testing is remains so manual?
At HP I think the number of products and rate of change in early development
made building fixtures to do this sort of thing pretty costly compared to low
wage human testers.

~~~
potatolicious
Regular testing that you'd expect to do many times, and that's part of your
product development process, is almost certainly automated.

But one-off tests are still squarely in the territory of Ye Poor Intern. I
remember interning at an auto parts plant years ago where I spent two whole
days stuck in a windowless lab where I laser-measured the precise diameter of
a batch of motor shafts because there was suspicion of a defect from the
supplier.

It's the sort of mind-numbing repetition and boredom that threatens to liquefy
your brain, and to this day gives me a greater appreciation for how good I
have it writing code for a living :)

(the fact that I was using _frickin' lasers_ to do my job was novel for only
the first half hour)

Certain _parts_ of automated testing are still manual too. In the
aforementioned plant I was responsible for going into the oven and making
measurements every few hours and measuring hundreds of things as part of the
heat-cold cycle testing, even though the actual temperature shifting and
vibrational stress was fully computer-controlled.

Good times. Glad I'm in software now.

~~~
hkmurakami
I have similar experience in an an auto-parts manufacturing setting, where
they had tried (and failed) to develop an automated system for their defect
testing. However, since the area was "visual defects" and not functional
defects (this certain component was in a very eyeball-attracting part of the
vehicle cockpit), it was discovered that humans are far more capable than this
kind of affair than computer vision at this time.

------
martin-adams
After 4 days 6 hours it did 36,720 iterations. After 10 days it failed on
37,112 iterations.

It takes 10 seconds per iteration. My calculations say it would have failed
after 4 days and 7 hours. I wonder what happened to the other 5 and a half
days.

Very cool experiment. It's this type of testing that makes me feel reassured
in mechanical engineering. It's about reassuring that a car air bag will work
after years of inactivity, or a car seat belt buckle will not break under
pressure in a collision. The only way to know is to test, test, test.

~~~
pcantin
I'm the guy that built it: During the tests, I had to guess the current count
based on the estimate that one full iteration was about 10 seconds. This was
not a good estimate and it made me overshot the actual number. When the test
was finally over I was able to see on the SD-card the final 'real' total of
37,112. I'm making a new video explaining some of this.

~~~
officialjunk
Honest question: do you think it matters that the bricks are attached with a
radial motion rather than linear? From my personal usage, I tend to press all
areas down at the same time rather than one side fully contacting before the
other. I would imagine the wear is different between these two cases.

~~~
pcantin
You're right and this is why I intend to build a better rig. More answers in
this new vid I just uploaded: <http://www.youtube.com/watch?v=VLt8HkIOAuY>

~~~
gvb
I like your plan of testing LEGO bricks[1] from different eras, but I would
recommend you use the same rotary mechanism for all the tests. If you change
the mechanism to a linear one, you won't be able to compare with confidence
the first (rotary) test with any follow-on linear actuator tests.

OTOH, if you repeat the (rotary) 70's era test with the linear actuator, that
would be interesting estimate of whether a rotary actuation is better or worse
for the brick longevity. Of course, you will still have a sample size of one,
so your confidence interval will be meaningless. I can see this turning into a
lifelong obsession... ;-)

[1] <http://aboutus.lego.com/en-us/legal-notice/fair-play/>

~~~
pcantin
Once I have a new test machine that his much faster I will indeed retest all
the eras (with multiple tests per era). Of course this time I plan to build a
real sound proofing system around it. This last machine was really annoying.

------
sramsay
I am so impressed by the mechanism used to hold and release the bottom piece
-- it's an elegant, simple solution that fully demonstrates why I lack the
talent to be a practical engineer.

~~~
jamesaguilar
It's not about talent, it's about practice. This isn't genius level
engineering, it's competence and experience.

~~~
pcantin
(I'm the guy that built it): Totally true, I build a lot of stuff and the goal
of this build was to make it work fast. In doing so I realized that I
underestimated the strength needed to assemble and disassemble LEGO bricks. I
actually planed to build a much better one using linear motion instead of
rotation motion.

~~~
jamesaguilar
And, just so it's completely clear, I'm also by no means claiming you aren't
talented (although I think the greater compliment is to observe that you are a
hard worker). I'm just trying to make sure this guy knows that what you've
done is easily within his reach, if he wants it and works at it.

~~~
pcantin
No sweat. your comment was right. I'm no engineer but I build stuff all the
time for the fun of it.

------
huhtenberg
Alternatively, don't use the bricks for 20-30 years and they will fail within
a dozen assemblies. Plastic loses its elasticity so the older bricks just
crack when are forced to connect.

\--

(edit) "Plastic" = "plastic used in Lego bricks that were included in Lego
Space sets sold in the early 80s in Japan."

~~~
kragen
"Plastic" is not one material, but many. Some degrade spontaneously over a
timescale of a few decades; others don't. Is your statement a result of
testing Legos, or a guess based on experience with other things, perhaps made
from a different plastic? Chuck McManis above said his experience was that his
40+-year-old Legos work fine.

~~~
simcop2387
Given that LEGO bricks are made of ABS plastic it very well could have had any
number of formulations where some years it was weaker than others. Should be
possible to test that.

~~~
jacquesm
Early bricks were cellulose acetate based.

~~~
simcop2387
Interesting, The Wiki says up until 1963, didn't know they changed the formula
at all. Be interesting to see how well ones from before and after the change
held up comparably.

~~~
jacquesm
I have a bunch of the very early ones, the differences with early ABS are:

\- changed shape slightly, some warping

\- the colours faded

\- they became quite transparent

\- they don't bind at all or very very loose

The early ABS ones are about as good as new other than being dirty and a
couple of scratches. No discolouration, they bind just fine, no warping as far
as I can measure.

~~~
simcop2387
Cool, they must have had some great QC with the ABS to do that well for so
very very long. I'd love to see the acetate ones in a picture if they went
transparent, that's a really neat "failure" mode.

------
tragomaskhalos
Related discussion about the durability of Lego posted a few months ago on HN:
<https://news.ycombinator.com/item?id=5040545>

PS: One of those strange and seemingly random usage differences between
British and American English is the latter's use of a plural, "Legos" (or
perhaps more accurate to say, use of the word "Lego" to denote "a Lego piece"
with resultant plural), which is never used in the UK and always sounds odd to
my ear (British Lego being like sheep ...)

~~~
dsr_
It's LEGO-fan usage more than British/American difference. A fan always says
"I play with LEGO, this is a LEGO brick, hand me some of that LEGO" whereas a
casual user might say "Scoop up some of those LEGOs; I play with LEGOs."

~~~
aardvark179
It may be a fan usage thing in American English, but I've never heard any
British person talk about LEGOs.

~~~
octotoad
Yeah, I've never heard anybody in Australia say "LEGOs". It's always been an
American thing to me.

Also, depending on the particular American accent involved, I often find the
pronunciation quite unusual. Sounds more like "lay-goes" than "leh-goes",
similar to the way some Americans pronounce the word "leg".

------
niggler
"It's long, noisy and cruel to LEGO bricks."

Now I'm curious: how well do the lego knockoffs hold up?

~~~
chris_mahan
From my experience, some of them don't even hold correctly on the first snap.
To be fair, they were not MegaBlocks, but some other cheap brand.

~~~
ktsmith
In the last year I've probably put together 20-30 sets of various size (50
pieces to 1000 pieces) and some lego don't hold at all out of the box either.
Lego is super easy to deal with for broken or missing pieces from sets which
is the only reason it doesn't bother me too much.

------
seivan
Seeing this want me to play with Arduino, not lego. I call this a success.
Going to look into Arduino now. Thanks!

~~~
hadem
I felt the opposite. Are you ever too old to play with Lego? :-)

~~~
bigiain
When you get old enough, you get to play with Lego _and_ Arduino (way more fun
than Mindstorm).

------
ChuckMcM
That was such a fun read. I have wondered about this but never tried it.

Strangely perhaps some Legos from my childhood still snap well (and they are
like 40+ yrs old). Kinda makes you want to figure out how the formula changed
over time.

~~~
elob
I highly doubt you used any of your pieces 37000+ times. You are not comparing
the right things.

~~~
ChuckMcM
I am sure I have not come close to 37,000 times. I have observed that Legos we
got for our kids vs ones that we had from when we were kids, are different.
I'm tempted to test both 'vintages'. I've also got some from the Lego Dacta
catalog when we were building robots out of Legos using the MIT 6.270 build
guides. They are slightly different too.

~~~
ricardobeat
Plastic has got a lot better, remarkably in the past 20 years. The new ones
are probably much more resilient.

fond memories of disintegrating rubber and plastic from the 90s

------
jdietrich
One of my favourite sales gimmicks is the wooden butt at Ikea - the testing
machine, displayed alongside the Poang chairs, endlessly "sitting" and
"standing".

<http://www.youtube.com/watch?v=4s_gyzshNPQ>

------
pcantin
I made the front page of Make magazine blog... Yeah baby!
<http://blog.makezine.com/2013/04/17/stress-testing-lego/>

------
tibbon
How many licks does it take to get to the middle of a tootsie pop?

~~~
ricardobeat
3481

[http://www.wolframalpha.com/input/?i=How+many+licks+does+it+...](http://www.wolframalpha.com/input/?i=How+many+licks+does+it+take+to+get+to+the+middle+of+a+tootsie+pop%3F)

------
avn2109
It would be interesting to see the cycles-to-failure distribution for these
parts. I wonder if the textbook "bathtub" curve would appear even for such a
simple piece.

------
xmmx
Why does everything have to be its own youtube video?

------
malkia
This... is... QA!

