Technic pieces always cracking

[Vissova]

I want to make a fuss about this because I just found a large amount of these pieces broken on my sets and I'm pretty frustrated about it, and I've never seen anyone else talking about this.

Technic axle connectors such as bushes (3713), cross-axles (32039), double axle connectors (32184), (really anything with an axle connection similar to the bush's design) are some of the most brittle objects ever created by mankind. I primarily collect Bionicle sets which have a lot of these Technic pieces, and for as long as I've built and played with them they've been a big problem. Even the 2015-2016 sets had these issues, in fact they were the worst offenders for whatever reason. I'm not rough with them or even build anything anymore, but just from very mild play and occasional posing they consistently crack and it's just ridiculous how fragile they are. I'm paranoid to even breathe near some of these sets now because I don't want anything breaking apart.

I don't even understand some of these pieces, such as 32039. Why is a part that's meant to sturdily hold axle rods in place so thin and fragile? Meanwhile a piece with an identical purpose, 32013, is thick and strong and never breaks because of it.

Am I just extremely unlucky or something? Does anyone else experience these problems?

 

[BubbaFit45531]

I haven't had Technic pieces break, but did buy a ton of Mixel balljoints and those became really loose. I had robot arm clutch pieces crack.

[Mylenium]

4 hours ago, Vissova said:

Am I just extremely unlucky or something?

Probably a combination of circumstances. If you're really into Bionicle, then many of the connections are not sound from an engineering standpoint to begin with. Too man single-point connections exposed to extreme forces. This could then simply be further be exacerbated by the models being "imbalanced" due to tiny variations with those axle connections causing further tension in the models. You know, most of your models are likely not really perfectly symmetrical and bend to one side or another. It's simply inherent in how LEGO pieces work and the tolerances they have. And finally, yes, of course there are recognizable design issues/ flaws in many of the elements you mentioned, as they intentionally are built to have a default negative tension that clamps the axles in place which then again is affected by the pieces manufacturing tolerances or even the color. So to get to a point: You could go through your models and check these things, substitute parts and so on, but overall you won't be able to mitigate this fully and will have to put in lifelong maintenance, occasionally even rebuilding the models every few years with swapped pieces. It's just plastic, after all.

Mylenium

[Vissova]

8 hours ago, Mylenium said:

If you're really into Bionicle, then many of the connections are not sound from an engineering standpoint to begin with.

Huh. So is the problem that these pieces weren't intended for action figures, as opposed to the more technical engineering behind regular Technic sets? I didn't think of that. Surely these pieces break often with things like Technic vehicle sets too, right? I imagine they're under a lot more stress with those larger builds.

[Mylenium]

8 minutes ago, Vissova said:

So is the problem that these pieces weren't intended for action figures, as opposed to the more technical engineering behind regular Technic sets?

On most "regular" Technic models those elements would often be bolstered by other elements left and right or "locked" in to minimize their movement, so yes, in my view it's probably a case of where the designs don't hold up to the way they are being used. At least the few Bionicle models I bought as used sets to scalp them for parts always had me going "SRSLY?" as they disobeyed some fundamental engineering principles (and by extension quite likely LEGO's own internal design rules). It only seems logical to me that they wouldn't withstand extensive handling for long or being post in unfavorable positions where the forces add up and certainly this wouldn't get better as the plastic ages and gets more brittle...

Mylenium

[Erik Leppen]

16 hours ago, Vissova said:

I've never seen anyone else talking about this.

Then, to be honest, you must be relatively new to the forums, because in the Technic corner of Lego communities, this is a frequenly recurring theme. All parts with "bush" style axle holes are prone to breaking, lots of people complain about it and strangely, people's experiences vary wildly. Example of a topic from 2015 here: Problem with Parts Cracking - LEGO Technic and Model Team - Eurobricks Forums (there must be more recent examples, but I couldn't find them).

In my experience, the axle-bush part you mention and the 3L pin with bush are the worst offenders of this problem. One particular use-case I have never fathomed was how the silver champion F1 car 8458 dared using this piece as a pushrod in the car's - otherwise brilliant - suspension system.

 

16 hours ago, Vissova said:

I don't even understand some of these pieces, such as 32039. Why is a part that's meant to sturdily hold axle rods in place so thin and fragile? Meanwhile a piece with an identical purpose, 32013, is thick and strong and never breaks because of it.

Just to make sure, we're talking about  and 

The design of the bush is like this, because it allows 8-tooth gears to be placed in the adjacent hole without touching. In older sets, when 8t and 24t gears were more common, this was very useful. Nowadays there are many more gear types, and 12t, 16t and 20t are more common, so there is less use for this. Angle connector parts #1 up to #6 don't have this feature, I presume because they were meant for cosmetic purposes, so they were expected to be much less often used nearby gears. Thats my guess for why this is different.

16 hours ago, Vissova said:

Am I just extremely unlucky or something? Does anyone else experience these problems?

As far as I know, there are people who have a huge amount of breaking parts, and there are members reporting having no problems whatsoever. I don't know what causes the differences, but I can only think of 2 causes: 1. there is a difference between parts coming out of different factories worldwide, or, 2. it's dependent on things like temperature (changes), humidity, sunlight, that differ between different people's houses or storages.

[howitzer]

I'm one of those people who have never had any problems with these (or any) parts breaking. In total I have had maybe 5 Technic parts to break over the years, including my and my brother's Lego in my childhood (25-35 years ago or so). Of those couple are 1L bushes, couple are toothed connectors and one of the first type of liftarm (2825) originating in 8868 was also broken when I put the set back together after 25 years of storage. I'm not sure but I have a very vague recollection of the oldest type of 24 tooth gear also breaking in my childhood.

As for the reasons, I have no idea why this happens to some people and not others, beside those that Erik listed.