Understanding Lego Part Numbers | Hacker News Reader

Understanding Lego Part Numbers

brickset.com

86 pointsadrian_mrd15 comments

It’s an ad-hoc system. Don’t try to look for a hidden beautiful logic. The “system” only makes sense to employees who’ve learned the numbers by heart. It’s trying and failing at keeping track of all the possible manufacturing processes, their related constraints (some elements only come in sets of different bricks, other come only in a minimum quantity). Also the nomenclature in house is a mess: terms like bricks, elements and parts are used interchangeably depending on the department.

Source: I worked at LEGO.

>The allocation and usage of LEGO part numbers is a complex subject that people have devoted their lives to understanding fully.

I hope that is something of an exaggeration.

I mean, LEGO employs some professionals who no doubt devote their career to understanding many things about LEGO. The part numbers, if assumed to also include things like brick stockpiles and production runs, planning of new bricks, set design requirements, etc. could easily be a major part of their job.

> LEGO employs some professionals who no doubt devote their career to understanding many things about LEGO

That is not limited to LEGO: Some researchers from Lancaster University also were researching LEGO bricks (read: Playing around trying to set record-low temperatures for LEGO bricks); and found out they're excellent insulators at sub-kelvin temperatures: https://news.ycombinator.com/item?id=21884755

Out of curiosity, what is a "sub-Kelvin" temperature? As an absolute scale, isn't it impossible to be off the bottom of that scale?

a temperature below 1 Kelvin.

Ah, thank you!

I have personally put lego bricks in 12T magnetic fields, embedded them in agar, accidentally irradiated them with 94 GHz microwaves, and blasted them with a lot of RF. Some of my friends have irradiated them (accidentally) at the diamond light source x-ray synchrotron, which can deliver MGy doses in a short period of time. Still others have used them as coarse positioning blocks on high end (read: homebuilt) novel forms of microscopes or other high-end optical equipment. They're fantastic for prototyping stuff quickly, or, in a pinch, acting as a dimensional reference. (Yes, really!)

You can put them in a vacuum. They don't degas much. They're magnet safe and can survive being in really high EM fields. They've got a high melting point. They don't become too brittle at sub-K temperatures. Blocks continue to mate as temperature varies -- Lego's process is fantastic at minimising temperature variation. They're really quite radiation resistant (many plastics fail horribly if you shoot them with >1 kGy). A child (or student!) can make a symmetric structure with them given a vague sketch design. A single "1x" wide Technik piece has a persistence length of about 80 cm. Structures you can build with lego are therefore really remarkably strong.

Every lego is made to insanely tight tolerances to published, well-known dimensions, and, best of all, if they break (an achievement!) you can buy another one for absolutely nothing in science-money terms. (The finance dept. look at you a bit weird when you put fifteen copies of "Spaceman playset" on an expenses claim form though).

I frankly think that most experimentalists somewhere in their life have some lego.

(I have a "Lego MRI" set that is only available to professionals!)

Out of curiosity, how do irradiated plastics fail? Do they become brittle, soft, something else?

The details are really, really complex, but either (a) they heat up from the absorbed dose (1 Gy is 1 kJ / kg) or (b) high gamma fluxes ionise CH bonds and cross link randomly, leading (typically) to brittle failure modes. Sometimes with heating you get spallation.

The accelerator I most recently used has a large set of house-grade UPVC glass windows around the target stage to help thermally control it (it's variable temperature). It's after the beam dump and behind quite a lot of lead, but they've been there for a while.

The glass is a weird shade of purple in a pretty gaussian pattern and the formerly bright-white UPVC is brown in places, purple in other places, and looks a bit like wood does when it's rotting and peeling off. If you hit it with a hammer I'm sure it would disintegrate. There are rad hard plastics but again it's all a function of "what radiation", "what energy", "how much" and "how long" and you end up doing monte carlo simulations pretty quickly.

I recently read that LEGO bricks put under compression (aligned with the studs in a standard 2x2) will liquify from the pressure before they break. Do you know if that's true?

But they don't have to reverse engineer the numbering system to find it out. Day one they just get told "here's how the numbering system works. Don't tell the Internet. kthx."

Given that part numbers are quite old, and that they rerelease parts with other numbers, you have far more faith in the ability to trivially understand legacy systems than I do.

They are probably told how to query the internal parts DB which is enough of a challenge just when searching by shape/color/version.

I doubt anyone at LEGO fully understands all of the naming/numbering convention decisions that have evolved over 70+ years.

I work quite a bit with numbering/naming systems for the oil & gas industry where I live; generally speaking there isn't a single system when things live for so long, but rather multiple systems, with each trying to fix issues with the previous one.

This is especially valid if you try to add any kind of logic or embed information in the naming conventions, as you'll quickly find out that the number series you allocated five years ago has proven to be too small.

And you can forget about scrapping everything and just creating a new system from scratch; all the documentation and drawings already point to the existing numbers, so the new system can't use an existing number but you have to map whatever you have to the new system... not unlike this[0] xkcd. And this is assuming that you've got loads of money to spend, and nobody cares how you spend it.

[0] https://xkcd.com/927/

Reply on news.ycombinator.com