When did TLG change the small posts on the underside of the modern bricks and plates , eg 1x6 and 1x4, to hollow ones?

  • 1
    As an aside, this change is probably still ongoing. New molds will be done that way (I assume to save on plastic), but replacing existing molds which still function perfectly just for this would be too expensive, so you'll still find both types in recent sets. No idea when it began, though.
    – Joubarc
    Commented Jul 26, 2012 at 18:27
  • In my 2012 star wars sets 9492, 9493 and 9495, the plates have hollow "posts" and the bricks have all solid posts, so I guess basically I have 2 questions, 1: when did they start to introduce the hollow posts? and- 2: did they stop using hollow posts for bricks or are they still phasing solid posts out? Commented Jul 26, 2012 at 18:57
  • 1
    Pictures? Not sure what you mean. Commented Jul 27, 2012 at 1:11
  • Basically I was answering 2. : still phasing out. But they probably won't force it, so it can take an awful lot of time. Also, while we AFOLs make a distinction between both versions, LEGO doesn't internally - as long as two parts have the same functionality, they're treated as identical.
    – Joubarc
    Commented Jul 27, 2012 at 5:49
  • 5
    Here's a pic of 1x6 plates as an example:- img28.imageshack.us/img28/6226/dsc01854il.jpg Commented Jul 27, 2012 at 15:16

3 Answers 3


I can confirm that some bricks have hollow posts. I ran across this in attempting to answer a "how much does a brick weigh" question. What I thought was a homogenous batch of bricks turned out to have a few with hollow posts. The bricks were all purchased new in the last three years.

From a "material cost productivity" standpoint, it will be in TLG's best interest to migrate to the hollow posts since parts from these molds will require less material to serve the same function (but not immediately). An expedient time to do this would be when a mold is at end of life requires replacement. So, I would expect to see significant variation continue for years to come. The balance point is the cost of replacing a single mold with the reduction in processed material costs over the expected remaining life of the mold. So the older the mold is the less cost effective it is to replace prematurely, but the newer one represents less time in service to amortize the mold over fewer piece parts... both of these things mean that the replacement will likely be when the mold normally reaches end of life. Since the useful life is very long, it is more likely that we are seeing parts from line or factory expansions.

  • I would tend to agree with all of this, and we've established that non-hollow tubes still exist as of today for various manufacturing reasons - but we still don't know when they started using hollow ones, which was the original question.
    – Joubarc
    Commented Nov 30, 2012 at 7:51
  • I was answering question #2 (ref comments). If we are going to have more questions like this, it would be helpful to get some current or former employees to join the group and respond. The original question will not have a simple answer. As a manufacturing process that would have needed to be developed, the TLG likely "used" solid posts long before they started shipping solid posts. Additionally there would have been a lag between shipping and customers seeing them. Commented Dec 1, 2012 at 14:10
  • I believe that hollow studs likely appeared long before hollow posts and the manufacturing process development required to achieve the hollow stud, led to the further improvements required to implement the hollow post. So what the original poster seems to really want for question #1 is a history with milestone dates for some indeterminate purpose. I'm better with the "why" on this than the "when". Commented Dec 1, 2012 at 14:13

Answering the question tl:dr style: Around the 90's.

Long story, quote from another user:

I recall having read somewhere that LEGO didn't replace all the molds in one go during the 90's. LEGO kept using the old molds until they were worn out. This meant that both solid and hollow tube bricks and plates were present in sets during that time, sometimes even in the same set.

This is an example of the main difference between plates:

enter image description here .

  • What I would like to find out was an article/video of someone who have actually found those different molds on the same set, but no luck for now. Commented Jul 27, 2020 at 16:26
  • i have an original 8440 from 1995. It has still solid studs on the 1x4 and 1x6 but hollow studs on 1x2 en 1x8 plates. Quote found on social media Commented Sep 7, 2022 at 10:06

I’m going through a Lego lot from the '90s (around '91 to '95) and there are some pieces that have a hollow bottom and some that have a solid bottom. On the other hand, I think the solid bottom was around in the early 2000s too. It just really comes down to the fact that there are many different Lego factories and they needed to make another mould of the exact same piece at different times because it’s being used more frequently. After they update the piece, in this case to having a hollow bottom, but sometimes they keep the old mould because it still works. I have gotten these sets and some colours had solid bottom and some didn’t in different colours so I imagine that in that factory one machine with the newer mould was making that piece in that one colour and the older mould was making it in the different colour. Even more annoying in that sealed set that I mentioned, there was even one colour with some pieces with hollow bottom and solid bottom but the set that I’m talking about is from 2003 and it’s not plates that I’m talking about but bricks. But if the solid bottom did not make it to the early 2000s then I would say the hollow bottom came out around maybe '94-'95 and probably did not retire the old mould until they needed to replace it with the updated version. But also one other thing too is if the piece was around early 2000s they might’ve kept the old mould in storage instead of destroying it in case they needed it if, I don’t know, it was busier that year, and they needed to take it out of storage or the other mould was down but it’s best to check if you see anyone opening a sealed set of the set that you’re getting pieces to it and see what mould variation is shown in the video on the set.

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    Commented Mar 15 at 15:52

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