How to make your moc more firmly?

[neonic]

Don't know it it's the right place for it? It's pretty 'universal' so ...

I was wandering how to make a moc more firmly. It's pretty universal but I mean mainly moc's of trucks. I've made a truck when I was young (it's a long time ago) and I had to pick it up pretty careful to move it, because otherwise it fell apart. Not fell apart in a lot of pieces but more like it 'break' apart or the cabine get loose of the chassis, that's kind of things. It's stands for about 20 years on the shelf. a Few years ago I modified the trailer a bit to carry a bottle of booze (empty one of course).

How are you do it? Are there some special ways / tactics for it to give it more strength / rigidity? I just wondering because I've seen a lot of cars and truck, wich are even bigger than my creation. 

[ExeSandbox]

Official LEGO sets are the best case studies for this. Due to LEGOs strict quality standards, their sets are built like tanks! (most of the time anyway.) But from what I've done and observed, a technic frame is your best bet. The bigger the model, the more rigid and well designed your technic frame has to be. 

[1963maniac]

I see you've been on EB a long time. Just build ... a lot of trucks. It seems like you like them so build many. You'll start getting it.

Go here https://www.lego.com/en-us/service/buildinginstructions and download all the building instructions you want.

[MAB]

For vehicles, definitely a technic frame. For other builds, make sure you attach as many studs as possible. If you have two halves joined by a single stud, then you are going to need to be very careful when lifting it.

[Mylenium]

2 hours ago, neonic said:

Are there some special ways / tactics for it to give it more strength / rigidity?

Well, you could buy a book on basic mechanical engineering. Really not much more than that to it. You know, basic engineering principles: Triangles are more stable than squares, single strut connections never work because they are prone to shear, box frames are more stable then single layer frames, you always need a t least three point connections to prevent unwanted rotations and so on, and so on.

2 hours ago, ExeSandbox said:

Due to LEGOs strict quality standards, their sets are built like tanks! (most of the time anyway.)

Not really. Some models are pretty terrible from an engineering POV. The point is not to "build stuff like tanks", anyway. You need to build your stuff to spec. Doesn't do you any good when a super-rigid frame on a car mangles your gears or way too many stud connections on a model cause so much internal tension, you get microfractures in the plastic. Overdoing things can just be as detrimental to your models as making them to flimsy. The trick is to find the right balance.

Mylenium

[Lira_Bricks]

1 hour ago, Mylenium said:

Not really. Some models are pretty terrible from an engineering POV. The point is not to "build stuff like tanks", anyway. You need to build your stuff to spec. Doesn't do you any good when a super-rigid frame on a car mangles your gears or way too many stud connections on a model cause so much internal tension, you get microfractures in the plastic. Overdoing things can just be as detrimental to your models as making them to flimsy. The trick is to find the right balance.

Could you give a recent example of a set you think is proper build, and one with terrible engineering? (Not picking a fight, I am really curious about your thoughts)

[neonic]

Thank you already for your reactions 
I've looking for the instructions for some Modelteam vehicles (because the truck is 'based' on the Highway rig). When I was young I had (and still) the truck and in the years is was many time re-build and modified and in the end it doesn't look like it at all anymore .
But .. the problem was, mainly, the chassis was a bit 'flexibel' and the cabin goes off pretty easy. I've playing with Mlcad a couple of times and I've seen that there are much more technical parts these days. Years ago I've bought a sportscar of Technic lego, don't ask why, and there were used a lot of parts I've never seen in my time, like those 'rounded' beams and triangles. So I can use such parts I think to make a chassis more firmly. 
Only I've no idea about the cabin yet. the Whole country is closed now for a while so I have plenty of time to figure it out.

ps. What do you prefer, the 'oldschool' technic or the new? and why? 

[Mylenium]

15 hours ago, Lira_Bricks said:

Could you give a recent example of a set you think is proper build, and one with terrible engineering? (Not picking a fight, I am really curious about your thoughts)

Good: 42069 - sturdy build, amazing details, just an awful color

Bad: Pretty much anything current to do with "cranes" - 42070, 42082, 42108. You know, those flimsy supports, bending outriggers and flip-flopping turntables. 42070 has a surprisingly sturdy chassis frame, though.

Mylenium