STEMFIE, a 3D-printable construction set toy | Hacker News Reader

STEMFIE, a 3D-printable construction set toy

stemfie.org

160 points_Microft31 comments

Very cool! I still think to date one of the coolest uses of 3D printing I've seen is the Free Universal Construction Kit[0]. There are adapters for any pairing of LEGO, Lincoln Logs, K'NEX, and several others. This is something that would likely never happen commercially due to licensing issues.

[0] https://fffff.at/free-universal-construction-kit/

I thought, that was an unfortunate choice of acronym. Then I checked the domain: Austria, home of the village formerly known as Fucking. So it tracks.

Hahaha it’s for sure 100% on purpose

I had heard of people creating adapter parts for different systems but from what I remember, these attempts were by far not as broad as this one. Thanks for sharing!

I like the idea of this sort of thing. Lots of different predesigned parts, cool, cool.

But it's axe grinding time.

As I recall from digging into STEMFIE a while ago (because I can't find this information on the site), they use some odd base unit like 12.5mm, which I assume is chosen because it's approximately half an inch (12.7mm), but "more metric". Which as far as unit systems goes, gives you the worst of both worlds, in that it will almost, but not quite, fit with your 1/2-inch based construction systems (like Erector Set/Meccano beams), and the metric numbers end up being not all that nice anyway (if you subdivide a beam in half or thirds you up with 6.25 or 4.167mm), so you may as well have picked exact compatibility with an existing system, anyway.

I wish people were less afraid to use "half an inch" as their base unit, if that's the size they want. It's as if they hear 'metric is superior' in grade school and think that means that real-world objects that happen to be designed around something other multiples of 10 of some metric unit are yucky and they'd better adjust it slightly so nobody notices, even if that means throwing out compatibility with a lot of existing stuff.

Okay rant over.

Lol I'm laughing about the time I designed a circuit board with standard 0.1"/2.54mm headers but accidentally ordered 2.5mm headers. The small 2-4 pin headers went in just fine and then when I went to put the big 20 pin header in... no dice.

Yep! The slight difference is often acceptable over short distances[1]. It's only when scale up that it becomes a problem.

[1] e.g. http://www.nuke24.net/docs/2019/JSTRCYMiniPVCompatibility.ht...

i have a vague memory that this was a cursed soviet standard, but i might be confabulating in my dotage

Isn't that just same as 10cm base unit with 8 subdivisions though? Doesn't seem that odd to me.

I mean 50/25/12.5/6.25/3.125 is a series that comes up all the time, it is not exactly uncommon to subdivide a power of ten by a power of two.

Yeah, the holes will match up with VESA hole patterns, I guess. But that's the only 100mm-based standard I can think of. I would have[1] chosen a size that matched with 2020 rails, or LEGO bricks, or Erector sets, or common lumber (1.5" is a multiple of erector set beams, so two in one if you go that route), or something.

[1] have. 1/3-scale two-by-two (1.5" square lumber)-based gridbeam actually works out really nicely.

This looks like it would solve a problem for me, thanks for sharing! Candidly, I'm a bit turned off by the name, the framing as a "toy", and honestly the ergonomics of the website (compared to similar systems like https://gridfinity.xyz/ or https://gridbeam.xyz/), but the underlying system seems like what I'm looking for.

I've been prototyping some models with a 3D printer, and have unfortunately been building my own sort of "construction set" so that I can minimize my print times and only reprint the parts that have changed. This means that I can mostly print flat pieces, which take an hour rather than 12 hours, but trying to invent a modularity system takes time (and iterations), which detracts from iterating on the thing I'm actually working on.

For anyone having trouble navigating the website, I'd recommend starting at https://www.stemfie.org/parts?view=category&id=14, or maybe skimming https://thangs.com/designer/Stemfie3D/sort/downloads if you just want to see the most commonly used pieces.

Yeah... I have a similar problem I want to work on in the coming months that I think people traditionally often used to solve with the help of Fischertechnik and the like, so this might be helpful there.

Do you mind sharing what you’re working on? I’m curious!

yeah, this website is like endless ikea. is there a word of explanation anywhere?

3D printing obviously wins for low barrier to entry, but I wonder if it wouldn't be faster and cheaper at scale to make some of those parts the "traditional" way with molds or such. Maybe worth a group buy?

Injection molds start at 6 figures and you need a different mold for every part.

Moreover, some of the STEMFIE parts have complex internal shapes and overhangs which would be extremely difficult to form with injection molding. Unfortunately, the same properties pose problems for hobbyist-level alternatives like resin casting, too.

I was looking at the threads/screws when I said some parts might be worth making with traditional methods, yeah. Even so, if you can make even some of the parts more cheaply/quickly it seems like a possible win.

Apparently, for low volume production you can 3D print injection molds.

Ex. https://all3dp.com/1/3d-printing-injection-molds-the-ultimat...

I've been doing this, and having a lot of success

Www.goldengatemolders.com

My favorite thing I've made so far in a 3d printed mold on my injection molding machines - screwdrivers. They say "Made with pride and love in San Francisco" on them and are made with ecycled plastic resin that is diverted from landfills.

Injection molds for small parts start at a few thousand dollars.

Source- I run a molding company

4 figures. You can get P20 molds, good for 20k cycles, <$5,000 in China. And of course, you can get family molds that make more than one part at a time, though most of the savings is in per-part cost.

> Injection molds start at 6 figures

This was the same 30 years ago. Why is this stagnant?

It’s not, xeometry can do it for much less! Or hubs.com (now part of protolabs)

That's not accurate anymore

You can get a aluminum tool for a few thousand, and even 3d print tools.

Source - I run a molding company that does so in SF

Www.goldengatemolders.com

Yes, if you want a stainless steel mold to very fine tolerances which will hold up for very long production runs.

There are more affordable options these days, but whether or no the newer options would be suitable for these parts or if these parts would be suitable for molding (usually that requires designing the part to take the requirements such as "draft angle" which helps get a part out of a mold) would be something which would need to be researched and accounted for and so forth.

Theoretically you could have a large mold with multiple different parts, kind of like plastic model kits.

I don’t think this is a name clash in any meaningful way but I’d nevertheless like to share that in Dutch, a “stemfie” is a selfie that you take from inside the voting booth and I love that we have a 7 character word for that.

As someone who studied privacy in voting, it's horrific that we have a word for this. Cat was out of the bag when the then-minister (of the interior) started pushing this. Somehow, despite the "how are you, fellow kids" vibe, the word became unstoppable.

Too bad no one explained the minister that we'd like to not enable vote buying (nor other forms of boter coercion).

(The official guidelines make a distinction between allowed - no info visible - and illegal stemfies, but no one's doing any enforcement.)

> in Dutch, a “stemfie” is a selfie that you take from inside the voting booth and I love that we have a 7 character word for that.

If we are talking about voting and words from Germanic languagues: with just one vowel difference (when pronounced), there exists the German (derogatory) word "Stimmvieh" [vote cattle]

> https://de.wikipedia.org/wiki/Stimmvieh

* for voters who vote for a party or candidate without informing themselves about their actual political goals and qualifications

* for politicians who vote for their party line because they fear sanctions if they don't

* for how politicans see their voters: just a stupid cattle that put them into power

That word also exists in Dutch, but as "stemvee"

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