Measuring The Lifespan Of LEGO


How many times can you put two LEGO pieces together and take them apart again before they wear out? The answer is 37,112. At least that’s the number established by one test case. [Phillipe Cantin] was interested in this peculiar question so he built the test rig above to measure a LEGO’s lifespan.

The hacked together apparatus is pretty ingenious. It uses two servo motors for testing, each driven by the Arduino which is logging the count on an SD card. One of the two white LEGO parts has been screwed onto an arm of the upper servo. That servo presses down onto the mating piece which is sitting inside that yellow band. Look close and you’ll realize the yellow is the handle end of an IC puller. When the post on the lower servo is moved toward one arm of the puller it grips the lower LEGO piece tightly so that the upper servo can pull the two apart. In addition to the assembly and disassembly step there’s a verification step which raises the mated parts so that a reflectance sensor can verify that they’re holding together. [Phillipe] let the rig run for ten days straight before the pieces failed.

Don’t miss his video description of the project after the break.

[via Reddit]

34 thoughts on “Measuring The Lifespan Of LEGO

  1. If he waited until he was able to lift the upper lego and the lower one didn’t raise with it before determinig that the lego had failed I’d say his number is way too high. As a parent, I’d suggest that the lego actually fails when the child that’s playing with it first complains that they no longer stay mated under normal use.

      1. That one’s been answered a long time ago. The owl said 3.

        Though, it really depends on the wetness of your tongue, the amount of surface area that contacts the tootsie pop, the saturation of sugar in your saliva after the first lick (at what rate your mouth waters and you swallow the sugar-saturated saliva), and the definition of ‘getting to the center.’ Can you just lick one side repeatedly, or does it have to be evenly licked (which never happens to me).

        So, we’ll have to be happy with 3.

  2. I’m a little surprised the lego didn’t outlast the test rig. The pull-apart force is pretty high, and he’s got it on the end of that longish arm. Tip: Separate your LEGO from the Megablocks. Both work, but if you put a “legot” on top of a Mega Block, they’ll push apart. Oh, yes, “legot” was my kids’ term for one lego brick. “Lego” seemed to them, the plural of “legot.”

      1. I got a MegaBloks battleship for my birthday probably close to 15 years ago. I opened it once, to try and put it together, picked up two pieces, got disgusted, and put them back in the box.

        I recently moved out of my parents’ house. When asked what I wanted done with the battleship, I said “Give it to Good Will.” It never got opened a second time.

    1. That’s easy: shake the box of Lego pieces before building the next project.

      In my days the Lego motors had no build-in or modular gearboxes, you had to build them from standard Lego parts. Especially the first few gears after the motor did wear out the shafts, and the pieces holding the shafts. The gears themselves did not wear much, but that could be the result of wear levelling: I had plenty of small 8-teeth gears.

  3. This is not A normal day test.
    You have to place the lego piece from different corners so it will wear out from different sides of the block.
    Maybe you can turn the block every time you put them together

  4. A machine to break toys? Isn’t that what kids are for? Neat build, but I have two suggestions, first the IC puller/gripper looks like it could fail fairly easy, why not drill a small hole through the middle (horizontally) and then use a rod to hold it during the pull phase? And secondly in the next iteration have some method to log the force needed to separate the bricks in addition to just the number of pulls to failure, this would be much more useful data.

  5. and yet i thought THE ANSWER was 42???
    on a serious note tho why would you want to know that? you could probably have asked lego themselves if they have any kind of serious quality control they could give you a number in a split second…

    1. They’ve got an amazing library of stats… And for a toy company, their engineers are some of the most specific and dedicated in the discipline. I don’t know how much the company is willing to divulge publicly, however. All that to say, if I needed to hire engineers and I saw Lego on their resume, I’d be *very* interested.

  6. Well, this is a pretty awesome test, but there are a few biases I can see.

    1. Drilling holes in, and screwing through a lego brick will weaken the plastic’s overall structure.

    2. The video shown doesn’t look like it is completely mating the two blocks. It looks like there is a slight gap when the servo pushes them together.

    3. Legos wear like any other connector, and if you always mate the same pieces, in the same orientation, they will wear some parts of the ‘clutch’ connection faster. It would logically follow then, that if you rotated the second piece 90degrees – even after failure – it would once again properly stay connected.

    1. I will aggree that this test is not a wholy “accurate” test, but it still produces results of a sort. Since we can reasonably determine that the two blocks are not fully mated, they are not rotated, and it is a one-block to one-block connection; I would say that 37k pulls should be considered a “lower bound” for serious testing.

      If we were to say that thirty thousand pulls were necessary before a LEGO really started to show significant loss-of-connection, that would mean; if I were to build three different projects from any limited collection of bricks, EVERY SINGLE DAY, I should have to replace those bricks about once every 27 years, 4 months.

      What that figure tells me, in a practal manner, is that any particular LEGO brick will probably be eaten by the sweeper before it ever shows wear fatigue.

      I don’t care if this test isn’t accurate, or only gives the crudest of information; it tells me that the LEGO blocks I had a kid will probably still work just fine when my great-grandchildren want to play with them. Since I hope not to have any grandchildren for at least three to five years, that is going to be quite some time…

  7. Kudos to the builder. I am always impressed when someone went out of his way to satisfy his curiosity. That’s a lot of work and the build seems to taken a lot into consideration. Very well made!

  8. One Test to Failure run does not answer anything. You need to have enough TTF’s to give a STATISTICALLY accurate answer. At this point, his answer is 37,112 with an error range of 100 percent.

  9. Kudos on the build. I always like to see people focused enough to create crazy contraptions like this.

    On a second note. They have these amazing medications for controlling OCD these days. I highly recommend that you speak to your doctor about the options. :-)

    1. OCD would be plugging and separating them manually. This is just a guy tinkering because he can. His reasoning may be flawed, but i’m sure he learned something in the process. Kudos to him.

  10. You don’t pluralize LEGO with an “s”, it’s one LEGO and it’s ten LEGO not LEGO’s/LEGOs.

    Sorry, I can’t help it. It’s just one of those things that bugs me. :P

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