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This blogpost on Technic Bricks briefly explains a few 'brick paradoxes' or dead ends. This particular model seems impossible to disassemble by hand:

enter image description here

How can I remove the axle without damaging/destroying the bricks?

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    There goes my "what's your smallest impossible-to-disassemble construction" question...
    – Joubarc
    Jan 11, 2012 at 5:36
  • This is kind of a hacky answer, so I am posting it as a comment instead. Get some glue, such as hot glue or craft glue. Apply a tiny amount to the end of a match, and then press that against the red axle. Repeat with the other side and leave to dry overnight. The next morning, use the matches (which have been glued onto the axles) to pull the axles out. Remove the glue by snapping it off of the axles. This only works if you use a glue that is not designed to work with plastic; that ensures that it will stick but come off relatively easily.
    – fouric
    Mar 27, 2012 at 15:51
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    Is there an axle in the other end too? If not a sewing needle can be used to push the axle out from the other side.
    – PGmath
    Jul 19, 2016 at 23:12

6 Answers 6

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I reproduced the problem and got the axle out using a sculpting tool (similar to an awl). It's a sharp point made of hard metal. (Soft metal will actually bend, believe me, I tried three tools.)

I inserted the point in the space left by the axle groove and pried the axle out. The point of the tool was against the axle while the body of the tool was pushing against the beam's rim. I made a short video to explain.

After looking at the pieces, I saw that it did however leave some damages to both pieces. On the axle it is barely noticeable, While the rim of of the beam has some little notches. Because of these small damages, it's not something I would do on a regular basis. On the other hand, both pieces are totally usable after the 'operation'.

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    Science. It works. Thanks for sacrificing your bricks for this, wish I could + a few more :)
    – Zhaph - Ben Duguid ♦
    Jan 11, 2012 at 7:57
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    I was thinking a toothpick wouldn't damage the bricks but be too brittle.
    – Ambo100 ♦
    Jan 11, 2012 at 10:53
  • how about the tip of a mechanical pencil with the lead retracted?
    – craigmoliver
    Jan 18, 2012 at 16:51
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    @craigmoliver That would probably break/bend the tip. Try it! :)
    – pcantin
    Jan 18, 2012 at 19:33
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    Remember that (at least the newer) axle joiners have holes in the middle, so once you have one out you can use a long tin object to push the other out. I'm wondering if you could use the notch in the 2m axles to do this without damaging it? I do not remember how I got it out myself when I experienced this paradox myself though. (I was like: hmm, if you do this you shouldn't be able to get it out... Oh snap...)
    – Sebastian Wahl
    Jan 22, 2012 at 14:53
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One option that may minimize damage to the axle would be to find a mini chuck (left) or micro chuck (right) (i.e. a very small chuck, like a pin chuck) with 4 collet prongs that stick out far enough from the nose cap and are small enough to insert between the rim of the hole and the axle:

Then you could tighten it down so the 4 prongs grip the cross shape of the axle tightly enough to pull it out. The match between the 4 prongs of the chuck and the cross shape of the axle will hopefully distribute the gripping pressure in a way that keeps the axle piece from being damaged.

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I once got myself into a situation much like this.

What I did was unfold a paperclip and insert the end of it into one of the four corners of open space of the hole that one of the axles was in. Then, I pulled the part of the paper clip out in such a way as to make the most friction between the paper clip and the axle, causing the axle to slide out a bit. I kept repeating this process until the axle slid far out enough for me to get a grip on it and pluck it out.

The tricky part was not pushing the axle back in when I was pushing the part of the paper clip in for another pull. I had to cause as little friction as possible when pushing the unfolded paperclip in, and cause as much friction as possible when pulling it back out so that the axle would come out with it.

This technique may be longer and more tedious than the others, but it uses an item that's almost certain to be lying around your house, and in the end it got the pieces apart without damaging them in the slightest.

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    I had a model using parts 18947 and 18948 built into a mechanism as shown on this page: newelementary.com/2015/01/lego-technic-new-parts.html (look for the picture on the right that says "NEW"). Unfortunately, someone had replaced the longer axle I had for driving on both sides with 3L axles. Using a pair of paper clips on opposite spaces on one of the 3L axles and applying pressure inward, I was able to pull it out and disassemble the model.
    – David Paxson
    Oct 19, 2015 at 19:10
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A pair of needle nose pliers might just do the trick, or some sturdy tweezers - however it might leave some scratches on the axle (thus limiting the no-damaging).

I assume there's another 2 axle in the other side stopping the use of a wooden toothpick or similar pushing it through from the other end? The joiner has an inner lip, but is hollow if I recall correctly?

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This answer will only work if there's enough of the notch in the size 2 axle available.

Use a piece of strong string (like dental floss), and tie a small slipknot in one end.

Using some other tool, such as a bent paperclip, push the lasso into the brick's hole down to the notch.

Using that tool, keep pressure on the knot area while you pull the slipknot tight. You don't want your pull to pull the string out.

If you successfully lasso the axle, you then be able to give it a straight tug out.

This should cause no damage to any parts.

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I have a small pair of bent-nose needle-nose pliers in with my Lego and use them quite often, generally without damaging anything.

enter image description here

That picture is a 150mm set, mine are a "miniature" 80mm set designed for electronics work. One key feature is that the ends of the jaws have little teeth, so they get positive grip on really tiny things. Of course, if you squeeze too hard you will mark plastic Lego pieces, but the bent nose helps as the jaws flex a little. I found bent nose works better than straight nose as I also use them to rescue small parts from inside big models. For that a long-handle set of pliers is also helpful, but those normally live in my electronics tool kits.

For the above puzzle, note that you should grab one side of the + axle, not the diagonal - the latter means all your force is going onto the edges of the plier tips and you will mark/damage the Lego.

(Echoing Zhaph - Ben Duguid above, but I actually do this rather than theorising about it, plus I wanted to include an image)

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