Is seating a Travis brick on a Technic pin a legal connection? TLG has used this construction at least once (M-Tron Particular Ionizer's "rotor"), but that was in the early 90s. Will this connection stress the Technic pin?

Here's an example of what I'm referring to from that set:

6923 step 17

3 Answers 3


In general, this sort of connection is illegal, but I think that it works fine with a Travis brick. Technic pins must be "in click" in a model, or the pins will be held in compression and can be damaged over time.

Here's a slide from Jamie Barard's classic "Stressing the Elements" presentation that explain the need to have Technic pins in click:

Technic pin in click

And here's the slide that explicitly states that Technic pins should not be used to connect to System bricks:

System brick and Technic pin

Here's an example of a set that didn't keep Technic pins in click and the resulting damage from prolonged storage assembled:

Legoland Germany Promo Set

With all of that said, the four holes that run through the stud connections on the sides of a Travis brick provide ample room for a pin to click into it. This isn't an obvious connection as with a Technic brick, but the fact the pin can move freely inside the brick indicates that it isn't in compression and is simply constrained to remain inside.

I can't speak to whether or not this type of connection would get through a design review today, but I can say with confidence that this wouldn't cause damage to elements. If this is considered "illegal" it would be for other reasons.

  • 1
    Great answer. Interesting to note is that a new macaroni was made with axle holes to account for this. Part no 25214 on Bricklink doesn't have any photos of the holes, but the instructions for 42122 Jeep Wrangler show the piece's practical use on page 167 as part of the roll cage. Commented Sep 15, 2022 at 20:42

Although technically the connection is illegal, I don't think the pin is under stress. I remember this set from my childhood, and the "rotor" rotated easily, which would not have been the case if the pin was stressed.


TLG continued to use this technique through at least the mid-90s. The technique appeared in the Cowboy sets 6761: Bandit's Secret Hide-Out

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and 6765: Gold City Junction

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to construct turrets.

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    Hi Mark, welcome to Bricks.SE and thanks for the great answer! I took the liberty to add links and images to the referenced sets and their relevant steps from the instructions, feel free to add or correct anything else too!
    – zovits
    Commented Nov 19, 2020 at 9:23

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