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At one point, Lego didn't really support putting a stud into a Technic hole, stating that it caused too much stress on the bricks. And for a while, there were no sets where that's the case. However, lately, I've been seeing several sets that do put the studs into technic holes; and I'm curious when that started.

There's an example of the technique here. You can see it with the trans-orange 1x1 round plate on the side and top that's attached with the stud in the Technic beam.

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I would have sworn it was still forbidden. IMHO this may be an exeption limited to such round plates. – Joubarc Oct 26 '11 at 14:12
FYI For those of us no living in the US that link may or may not work. The set is Bucket Truck 8071 – Cameron MacFarland Oct 30 '11 at 3:18
I'm not seeing that construction anymore in the most recent (we own) sets. It looks like it has been replaced by half-pin inserted into technic holes, and the end of the half-pin is used as a stud. – Stephane Delcroix Jul 8 '14 at 9:20
That's interesting. I don't think that would be as strong a connection, and it inverts the direction of the stud - the stud would face away from the hole, instead of in the hole. – Grandpappy Jul 10 '14 at 21:52
up vote 22 down vote accepted


Lego's official position on this technique was explained at Brickfest 2006. Jamie Berard, then a relatively new designer in Billund gave an excellent presentation on why certain techniques are considered "illegal" in official sets. The basics message is that building techniques should:

  • not stress the bricks
  • be suitable for the target audience of the set

He described in some detail the ways that Technic beams and regular system bricks can and cannot be combined in official sets. The main problem areas occur because:

  • Technic holes don't exactly line up with the studs on the sides of system bricks
  • the holes in Technic beams are slightly smaller than the ones in system bricks

The implications are:

  • Although system brick studs can be inserted in the holes in technic beams, this should be avoided where it would be difficult for children to take apart. Jamie gives an example where a brick has a single stud inserted into a beam, and describes it as "tehnically legal" (but not recommended). This is the situation in your example.
  • Where the combination of Technic and system bricks results in an assembly where components interfere with each other, this can stress the parts. However, this is not the case in the example you cited.

According to these rules, then, the example you give is not illegal. Clearly, it can be a problem under some circumstances, but is acceptable under others.

Unfortunately, none of this actually answers your original question, as there remain two possibilities:

  1. Your assertion that "at one point, Lego didn't really support putting a stud into a Technic hole, stating that it caused too much stress on the bricks" may not be correct. The misapprehension may have arisen because Lego emphasised the illegal uses of the technique, but down-played legal ones. In that case, we may assume that set designers simply chose not to use the technique (or were unaware thay they could because they, too, were misguided).

  2. The alternative explanation is that Lego did make a sweeping statement to this effect, but later realised that it needed clarification. In which case, Jamie's presentation in 2006 seems to be the first clear public statement of the more detailed rules (of course, internal designers might well have been aware of the policy tweak much ealier, but still chosen not to use the technique). If there was such a policy adjustment, this would establish why the technique was not used until recently.

Without the text of Lego's earlier communications on the subject, it is difficult to know which explanation is the correct one. Either way, I'd urge you to look at the slides for Jamie's presentation. It is available online in powerpoint format and as a pdf. Apart from being an interesting read in their own right, they also make it clear that this single stud-in-a-hole has been legal since at least 2006.

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Wow. Great answer. I had not seen the slides before. You are correct, the slides explicitly state that the use we're now seeing is legal. – Grandpappy Nov 3 '11 at 14:09


When Technic was first introduced.
Check out this alternative build of set 850:

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Nice find, Niels. – Kramii Jan 12 '15 at 10:38
Oh, I wanted to show off with the "ancient" 8480 Shuttle from 1996... – zovits Sep 15 '15 at 19:56
This seems to be a case of "Legal then, illegal now" as per pages 27-29 of the earlier mentioned presentation. The deck mentions that single stud in hole connections are allowed, but not multiple studs (slide 11-12 of the same deck) - BTW, your picture immediately took me back to my childhood - I built that roadgrader several times as a child. Amazing how one's memory works :) – Phil B. Sep 18 '15 at 2:00

Seems to have really come into use this year. The Winter Village Post Office (pages 65-66) set also uses it for a larger piece with a SNOT block holding the window roofs on:

SNOT Block attached to 1x2 Technic Brick Hole

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I hadn't seen that yet. It looks like they are keeping the technique to just a single stud in a single hole. That's interesting! – Grandpappy Nov 2 '11 at 18:31
The technique isn't new this year: the The Emerald Night (which appeared in 2009) uses the single stud-in-a-hole technique for the details on its carriage. – Kramii Nov 2 '11 at 21:53
See pages 11-12 of Jamie's presentation in Kramii's answer - you'll see that 1 stud in 1 Technic hole is OK, provided a few other rules are respected; more studs isn't as it would be too hard for children to pry apart. – Joubarc Nov 8 '12 at 9:12

Good question, but I think the example shown demonstrates where Lego currently accepts this kind of construction; i.e. only for small, decorative components and not for major structural interfaces.

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Yes, but it seems to be a technique that is fairly recent for the company. My question isn't about how Lego uses this technique, but about when they started using it. I don't know of any definitive set when they began using this technique (it's been used by AFOLs for a long while). – Grandpappy Oct 27 '11 at 13:44

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