This question might be strongly opinion-based, but I also think it might be interesting. I know there is a guide for Lego builders to decide if their build is legal or not. However, the cases of this guide focus on assemblies where the final configuration has some issues with friction or internal stress. But at the same time, there are assemblies, which do not deal with either of these, except at the moment when they are put together. Here is an example: enter image description here

Is this considered to be legal or not? If not, what about this one: enter image description here

  • 8
    What's wrong with items in a second picture?
    – Alex
    Feb 18, 2020 at 22:06
  • 1
    Similarly to the first assembly, it does not have any internal stress when it is assembled even though the bottom is definitely deformed when you put them together.
    – BalazsToth
    Feb 18, 2020 at 23:17
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    Every pin is under certain stress while it is being pushed into hole as well, but these have been designed to withstand it. The part in your second picture is kind of same. With exception being rarely disassembled.
    – Alex
    Feb 19, 2020 at 6:18
  • 5
    These should probably be separate questions! The first has clearly been forced, even if it's possible to create, while the second is an official assembly.
    – ti7
    Feb 19, 2020 at 20:58
  • 1
    The bottom picture looks like it was made originally so. I'm sure I've seen a combination like that before. What made you think it's not original?
    – Mast
    Feb 20, 2020 at 13:22

2 Answers 2


The answer depends on your definition of "legal". In the strictest sense, it means "can be used in official LEGO sets", and in this case, this is definitely not legal, as the axle is not designed to bend that way, unlike the many various hinge and joint pieces.

On the other hand, "legal" might mean "does not cause damage to the pieces", and in this sense it is a borderline case, as you can see the end of the axle retaining its slightly bent shape, but it's nothing that couldn't be fixed with a little more force applied in the correct place and direction.

Whereas on the far end of the legality spectrum, the status of any technique or piece is subject of individual opinion or decision. You are certainly free to employ any combination of parts, use 3rd party parts, paint, glue or cut pieces to your heart's content and shouldn't fear any reprisal from the LEGO Police. Collections curated by others, events or competitions might (and often do) apply a restriction on at least a subset of these, so if you are not in the position to judge the legality, it's best to directly ask those who are.

EDIT based on Michael's comment:

Another criterion in the definition of legality is often "can be easily taken apart by a child", which this design is clearly not.

  • 3
    Another criterion in the definition of illegality is often "can be easily taken apart by a child". Would say this example fails at that also, especially if there's technic built onto this construction. Feb 19, 2020 at 11:14

From LEGO point of view this definitely would be illegal to assemble such axle with particular frame since you cannot build and then take this apart without bending the axle.

But from AFOL's point of view this could be a doable solution for a MOC if there is a real need. There's plenty of space to bend the axle and it won't get damaged.

  • I think I've actually seen that kind of axle assembly in Technic sets before, or it could just be me not realizing how to put it together without bending pieces... Feb 19, 2020 at 4:53
  • 11
    @technicguy1 If you can find any official examples of such construction, I'd be certainly interested in seeing them.
    – zovits
    Feb 19, 2020 at 9:38

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