Different types of brick tubes (hollow vs. solid)

Berbatov

Hi,

I'm currently going through a Lego lot with a variety of standard bricks (2x1, 3x1, etc.). For the first time ever, I've noticed that there are two types of those bricks - those with a hollow tube and the bottom and those with a solid tube. Please see the picture below.

When breaking the lot into the individual sets, I obviously don't want to mix those two types (i.e. a set should only feature one of them). Is there any way to distinguish whether a given set did originally contain the hollow or the solid bricks? In the instructions, they are only listed as 3004 (using the 2x1 as an example).

Thanks

Paperballpark

No, because Lego class them as the same. Heck, even BL do.

I've always assumed the hollow ones are newer, as it will save a small amount of ABS on each brick.

HugeYellowBrick

I've seen reports that both types occur in some examples of some sets.

Bobflip

There wasn't a clear cutoff date, I found this from 2012 but there's probably more info out there. I try not to get too caught up in getting it exact if the sets are for my own use. Most of them get parted out to colour/type storage in the end anyway so I'm less fussed by it now! If I'm selling anything on I'll try to use a type that would have come with that set, and if I don't have all of them I'll use the other type where necessary and mention on the listing.

https://bricks.stackexchange.com/questions/1493/lego-with-hollow-posts-underneath-dates

LusiferSam

I first noticed this in 2002.  I had ordered a parts pack and saw the hollow pegs.  I don't know exactly when the transition took place (there would not be a hard transition anyway).  In generally speaking sets before 1990 all would have solid pegs and sets after 2004 all have hollow pegs.  

On Bricklink people add descriptions to their inventories.  This is how I search of stuff like, Pat Pend, void, pip location, etc.  For some people (like me) it matters that you are using period correct bricks to complete a set.  If you can offer that, I'm will to pay for.

CCC

Paperballpark said:

No, because Lego class them as the same. Heck, even BL do.

I've always assumed the hollow ones are newer, as it will save a small amount of ABS on each brick.

I thought that this was to do with cooling rates and being able to take them from the mould slightly quicker, thus more efficient in terms of production.

Aanchir

CCC said:

Paperballpark said:

No, because Lego class them as the same. Heck, even BL do.

I've always assumed the hollow ones are newer, as it will save a small amount of ABS on each brick.

I thought that this was to do with cooling rates and being able to take them from the mould slightly quicker, thus more efficient in terms of production.

This definitely seems more likely to me… for most LEGO pieces, the material cost of the plastic tends to be much less than other production related costs like the complexity of the molds or how many copies the mold can churn out in a given stretch of time. I suspect the size/mass of parts has a bigger impact on costs on the distribution and shipping end of things than the production end.

Also, with thicker parts, even if you allow them more cooling time, there's the risk that the outside of the part will cool faster than the inside, which can result in deformation (e.g. an indentation on the outside of the brick). This certainly isn't a huge concern with something as narrow as a 3.2mm shaft (which is basically the same thickness as many minifigure accessories), but I wouldn't be surprised if hollowing out the shaft still helps to ensure that more of the parts meet quality assurance standards and fewer get rejected prior to packing.

Sometimes there are also some structural advantages to parts having thinner walls when it comes to clutch power. The switch in 2x4 bricks from thicker walls that are smooth on the inside to thinner walls with little ridges that hug the studs is another example of a design change AFOLs often attribute solely to cost-cutting (especially when it results in certain colors of brick becoming less opaque), but the reality is that it has more to do with clutch power and preventing deformation from uneven stresses on the interior of the brick, as illustrated and described here: https://flic.kr/p/L6G7ed

Berbatov

Thanks for all the feedback, very interesting.

It seems there is some variance in when Lego started adopting the new (hollow) standard. As I'm trying to separate out a lot into individual sets, I guess year of release is the only information I have to pick either solid or hollow bricks.

I'm currently separating out the Pet Shop (2011) and the Tower Bridge (2010), so it seems that doesn't help much (as it's in between the two dates mentioned in the thread above).

Is it correct to assume, that a given set has only one type of brick? Then I could go by the availability in my lot. I.e. if the instruction asks for six 6x1s and my lot has ten, 8 of which are hollow, the set must have used those (as there are not enough solid ones). This obviously assumes also that the lot is not a total mess and more or less still contains the original material.

Istokg

From a historical perspective TLG has always mixed parts from different molds in the same sets.  Just like the old light gray parts, replaced by new light bluish-gray in 2003 have been mixed together in the same sets (for years thereafter... as late as 2009 for some sets), so too have different minor mold variations been found in different sets.

For example, the Homemaker sets of the 1970s, always found with a lot of tiles in their set inventory, has many sets with the 1965 introduced "tiles without grooves" and 1973 introduced "tiles with grooves" mixed together in Homemaker sets.  I once had a (1974) mint 266 Child's Bedroom Set with red and black tiles with the grooves, and the white tiles without the grooves.

I have seen 6075 sets (USA version of Yellow Castle) with bricks of the same size have a mix of the bricks with the moulding pip on the studs (newer), and moulding pips on the short side of the bricks (older).   The list is endless...

The oldest known model (that I am aware of) with a mix of elements from different periods was a 1236 Garage set of 1955-57.  During the slotted bricks era (1949-56) LEGO parts had slots on the side of the bricks (to hold in the studless top windows, doors, and a few other parts).  In 1956 the slotted bricks were replaced by non-slotted hollow bottom bricks.  However... TLG still had a quantity of the older garage doors/frames/bases (for use with the older slotted bricks) in their newer parts inventory.  Since TLG... 'NEVER THROWS ANYTHING AWAY'.... they decided to use the new LEGO parts with their leftover older inventory....



So... since TLG wanted to use up older parts inventory... the older garage door frame (without studs on top, but with "4 wings" on the side)... were held in place by slotted bricks.  Starting in 1956 (when the slotted bricks were replaced with regular bricks)... 4 older slotted 1x2 bricks were included in the garage kit (on the left side of image) to hold the older garage door/frame in place.  This was an interesting way to prevent TLG from discarding older parts. 

TLG has always used up old inventory when mold changes (new part type introductions) were made to LEGO sets.  As I already mentioned.... TLG never threw anything away.  And this makes some buyers of LEGO sets think that that their sets have parts that really don't really belong in their sets, when they actually do!  The number of sets that have this issue probably number into the thousands!

I'm sure this has driven Bricklink catalog/parts admins crazy!  ;-)

Aleydita

Earlier this year I opened a sealed box of #2000211 and the lime 1x6s were of both varieties.