Filled studs vs. unfilled tubes on the bottom???

[ChrisXY]

Hi,

I have a bunch of LEGO. The plates and bricks are looking the same at the top, but from the bottom some pieces have filled tubes and some dont. That applies to bricks and plates. I have read that they changed it to minimize plastic and save money.

So my question is, when did they change it?

As I want to sell my old and new LEGO. Does it make a difference? Should I be careful not to mix them up?

[JesseNight]

I suppose that depends a bit on potential buyers, but I can imagine collectors preferring parts to be accurate for a model and at least consistent (not mixing old and new within a single model). Can't talk for everybody though.
Which parts specifically do you mean with the tubes? (or better yet, do you have pics?)

[ChrisXY]

Yeah, take a look here. This also goes for bricks ("single" ones like 1x2)

I know that the left one will be older. But I want to know when the change was made. E. g. I own The Black Pearl. Unfortunately all bricks are in one huge pile with thousands of other ones ranging from 1970 to 2025

If I want to sell my Black Pearl, I want it to be as original. Not mixing new and old grey is super simple. But what about the (un)filled studs. Also what comes in my mind what can be important are the modified 1 x 1 with U Clips; it doesnt stop here as all plate with clips have more and more variants. It doesnt stop there as I have to be careful not mixing reddish brown and (old) brown. Super annoying...

Edited April 18 by ChrisXY

[Stereo]

As far as I know in the 1990s Lego mixed the solid/hollow tube plates in sets, and has never distinguished them in part numbers, whatever made them change the mold wasn't urgent enough to immediately remove all the old molds from service.  I'd tend to look more at the underside printing to figure out part eras.  Very early parts often have nothing at all, or "Pat Pend" for larger parts, then they added mold numbers, then in the 80s they put part numbers in, then additional (C) LEGO mark, and then in the early 2000s they went to a more consistent (and smaller) font.  The underside of plates also got updates on the bottom flat surface; early pieces are actually flat, late 90s/early 00s ones have a slight step where the inside is recessed, and modern ones have trapezoid marks in them, usually about 1 every 2 studs.

 

If you really want to get into it, a lot of parts also had the injection point moved from the side of the piece to the middle of a stud (1x1 round plates did it fairly late, maybe 1995-2000, other plates earlier, like 1x2 jumpers have it in the stud since maybe 1985)

Edited April 18 by Stereo

[ChrisXY]

Thanks for the answer. But can we say when LEGO had only unfilled studs below? That already would help a lot. If they started to mix in 1990s, they probably changed full in ~2000?

Edited April 19 by ChrisXY

[Stereo]

The newest I've personally encountered is Medium Blue 1x2 brick with solid studs, which has to be 2002 or newer.  Plates seem to have been done by 2000, yeah.

[ChrisXY]

To understand that correctly my Black Pearl from 2011 should have single plates only with unfilled tubes at the bottom?

But what about the bricks? If you say you have 2002 bricks with filled tubes...when was the change? 

[TeriXeri]

I think I remember open tubes as early as the 90s , 4559 Cargo Railway from 1996, as I  took apart and rebuilt that set multiple times at the time, I remember 1x6 plates having open tubes (22 in black , 11 in yellow in that set)

 

But LEGO still uses mixed mould types even now,  for example inverted 2x2 slopes sometimes have different bottoms.

Edited April 19 by TeriXeri

[anothergol]

Also, side notches (well, for 1 by X parts) > tubes. IMHO Lego should ditch the tubes entirely.

[ChrisXY]

So the question remains, how important is the correct mould in a very expensive set? And how can I find out, which moulds were used... For the clips it is at least shown at bricklink.com. Same goes for open studs or hollow studs. But for bottom tubes there is no info

[JesseNight]

46 minutes ago, ChrisXY said:

So the question remains, how important is the correct mould in a very expensive set? And how can I find out, which moulds were used... For the clips it is at least shown at bricklink.com. Same goes for open studs or hollow studs. But for bottom tubes there is no info

I think the question is... how important is it to you? Or anyone buying it? The answer is just personal. Some people would be bothered by it, others wouldn't be.
I know in case of those plates with hollow studs, they often got mixed in the transition period and they have no different number. The use is not different either. I would personally only be bothered if it were visible and ruining the symmetry of a model.
In case of 1x1 with a clip, the model numbers are different and you notice it in use too. The thick ones (C) are obviously sturdier and therefore I'd prefer them on a connection that often gets separated. I've had some old thin ones (A) break on frequent use. But those were great to allow a tool like a minifig radio to freely rotate, something you couldn't do on the thick ones. The newer ones (D) are the best of both worlds. Guess that's just evolution.

As you already noticed yourself, for clips you can check on the model. For tubes, don't worry about it. No Bricklink store or even Lego themselves would make a difference between the 2. I'd only do it if it's very obviously visible in the finished model, or if a buyer specifically asks about this.

[MAB]

On 4/18/2025 at 7:36 PM, ChrisXY said:

Hi,

I have a bunch of LEGO. The plates and bricks are looking the same at the top, but from the bottom some pieces have filled tubes and some dont. That applies to bricks and plates. I have read that they changed it to minimize plastic and save money.

 

I thought it was to reduce thickness of the thickest part to allow quicker cooling and hence higher production. 

[SNIPE]

I prefer side notches too IMO, I think all hollow tubes should accept a mini-peg (but most do not in reality), not a huge deal but LEGO is meant to be a system remember, and could do with some more foresight in places.

I'm not sure about having all studs semi/fully hollow , it would add a whole level of building possibility which is indeed very good, but studded models would look bad.

However most lego sets are tiled off anyhow! its not like the old days.

You can sometimes just fill an open stud with a 3L bar but I wish lego  would make a (just slightly less than) 2L bar so that I don't have to cut doen rigid hoses. The reason I said just less than 2L is  because some pins (and other parts) have barholes that are not quite 1L deep.

[anothergol]

On 4/21/2025 at 5:59 AM, SNIPE said:

I'm not sure about having all studs semi/fully hollow , it would add a whole level of building possibility which is indeed very good, but studded models would look bad.

Funny, I much prefer semi/fully hollow studs, visually.

I sometimes have them on purpose in my MOCs, while I (try to) never expose studs with logos. Why? Because from distance, the Lego (or any) logo looks like dirt. I treat them the same as mould marks (and they often have one on top of the logo, to make things worse). It's detail that's not at the same scale as the model you're making, looks bad IMHO.
But open studs, or even plain studs without logo & mould mark, I like them visually.