[HELP] Generic Building Help Topic

[Jurss]

Can You just position it on axle, if that halfbeam is with some axle holes?

[howitzer]

14 minutes ago, Jurss said:

Can You just position it on axle, if that halfbeam is with some axle holes?

Sure, but it doesn't stay in place very well, as there's moving parts involved and friction alone isn't high enough to keep it firmly in place. Of course I could increase the friction by adding more bushes, but then it becomes pretty cumbersome.

[vascolp]

If I understood your problem, minifigs can give you a hand… or rather two.

Not perfect, there is a bit of tension and you get two protuberant radius bones...

[Andman]

On 7/1/2021 at 7:03 PM, howitzer said:

Does anyone know a way to create a quarter stud offset? Ideally a spacer (like bush or something) but other methods can also be considered. I know such an offset could easily be created by placing bushes and aligning them carefully on an axle, but those are prone to unintentional sliding, and I'm wondering if anyone has come with a better method...

Not an expert but may be this thread can help:

 

[howitzer]

22 hours ago, vascolp said:

If I understood your problem, minifigs can give you a hand… or rather two.

Not perfect, there is a bit of tension and you get two protuberant radius bones...

<snip->

 

I'd like to have something with no tension, but might give this one a try anyway, thanks for the tip!

11 hours ago, Andman said:

Not an expert but may be this thread can help:

 

Oh, I didn't remember about this topic, gotta check it out and see if it's any use for my purposes, thanks!

[vascolp]

38 minutes ago, howitzer said:

I'd like to have something with no tension, but might give this one a try anyway, thanks for the tip!

[This] might be a good option, I did not try it, I don´t have them available:

or maybe other thing that hangs on minifig neck...

[howitzer]

13 hours ago, vascolp said:

[This] might be a good option, I did not try it, I don´t have them available:

or maybe other thing that hangs on minifig neck...

That appears to be 1/20th of stud too thin, but probably the closest thing there is.

[Mechbuilds]

Can anyone help me with a gearbox for my chassis? 

Basically i need a gearbox that has a speed for crawling and a speed for moving around. 
My axles have planetary hubs so i need to speed up the motor output so it won't just move on a snails pace. 
But i also need a slow speed rock crawling gear. 

Space is very limited.

 
chassis.lxf

I was toying with the idea of having a lockable center differential.. But i'm not sure if there is enough room.. 
The lower J beams can be removed if needed but the links need to stay there.. The chassis can be extended by 1-3 studs if absolutely needed. (will affect rock crawling negatively.)

I'll be using buwizz.. 
For motors i'd prefer using two L motors for higher speed and combined torque. But XL motor is fine too if it's sped up a little bit by gearing it for higher speed and lower torque. 
As long as there is a gear for crawling.. 

M motor for gear selection is cool but not necessary. 

I'm terribad at making gearboxes. Don't understand them at all. To me they're just boxes of mishmash and magic. 

[Hrafn]

Does anyone have examples they can point to of using pneumatic cylinders or pumps for shocks in vehicle suspension?  I am working on a model where the real car has separate springs and shocks (i.e. not coilovers), and was curious to see how well this setup works in Lego.

[weavil]

@Hrafn  So like a leaf spring with pneumatic or a shock paired with pneumatic cylinder? There is this: 

 

[Hrafn]

1 hour ago, weavil said:

@Hrafn  So like a leaf spring with pneumatic or a shock paired with pneumatic cylinder? There is this: 

 

Thanks!  I am not trying for adjustable ride height, but yes that looks similar to what I am thinking about.

[Andman]

9 hours ago, Hrafn said:

Does anyone have examples they can point to of using pneumatic cylinders or pumps for shocks in vehicle suspension?  I am working on a model where the real car has separate springs and shocks (i.e. not coilovers), and was curious to see how well this setup works in Lego.

I'm using pneumatic cylinders as suspension in a truck. They are working quiet well.

suspension_test.mp4

Edited July 26, 2021 by Andman

[Milan]

Not really an impressive image, but nevertheless:

3 axle, 1:13 crane.
12 small pneumatic cylinders and 6 springs. When height adjusted to max, via pump, the cylinders perform like shocks, in combination with the 6 real shock absorbers.
It worked really well, even for the 10kg+ model.

[Hrafn]

Tha ks to you both!  Good to know the idea isn't crazy.

[StudWorks]

Hi. I'm working on my first 1:8 scale Technic car and while building it I used other MOC instructions for inspiration, and I wondered, how do master supercar/scale technic model car builders learn how to build their own chassis, axles, and exterior?  I can't really build my own axles/chassis without learning from the instructions of other MOCs, and I'm really curious about how all of the best Technic supercar MOC builders learned all of their master building knowledge with exterior and chassis building.

[2GodBDGlory]

5 hours ago, StudWorks said:

Hi. I'm working on my first 1:8 scale Technic car and while building it I used other MOC instructions for inspiration, and I wondered, how do master supercar/scale technic model car builders learn how to build their own chassis, axles, and exterior?  I can't really build my own axles/chassis without learning from the instructions of other MOCs, and I'm really curious about how all of the best Technic supercar MOC builders learned all of their master building knowledge with exterior and chassis building.

Well, I'm certainly not one of the best, but it was all trial and error for me...

The website Sheepo.es has some interesting suspension designs in the MPS section that may be educational to you, though.

[weavil]

1 hour ago, 2GodBDGlory said:

Well, I'm certainly not one of the best, but it was all trial and error for me...

The website Sheepo.es has some interesting suspension designs in the MPS section that may be educational to you, though.

That feeling when you don't need to rebuild half a car for the 12th time!

 

6 hours ago, StudWorks said:

I can't really build my own axles/chassis without learning from the instructions of other MOCs, and I'm really curious about how all of the best Technic supercar MOC builders learned all of their master building knowledge with exterior and chassis building.

Trial and error. However when they find something that works, they will use it over and over (mainly car/truck suspension). Trial and error can sometimes take way too long depending on the type of project (like equipment/machines).

[Keegan Pilling]

I’m hoping some of you could help me out.

I’ve been working on an RC telehandler MOC for the last few months now, and am (hopefully) in the final stretch of the build.

I was first inspired by Eric Trax’ CLAAS Scorpion 756, but due to my lack of parts, as well as the limitations of LEGO motors, I wanted to make mine more compact, and hopefully just as functional. I have mostly completed the chassis, but am hung up on the arm.

 I am hoping to make the arm fit the scale of the rest of the build, meaning it would have to be 4 studs wide, and 4 (maybe 5) studs high, however, I can’t find a way to do this while also allowing the arm to extend another 26 studs, the length of the two 6114979 gear racks I’m planning on using for the extending part of the arm. On top of this, the arm needs to have some sort of mechanism for tilting the forks/bucket. This can be done either with a linear actuator, which would be difficult to incorporate as it would be difficult to fit a motor in the end of the arm (as Eric Trax did), or with an axle utilizing sliding gears running the length of the arm. The problem with that design is that I would like the axle to fit within the 2x2 confines of the extending arm, for a more uniform look. However, the only way to fit an 8 tooth gear on that axle would be to have it on the back end of the arm (which will be hidden inside the outer arm. This will add at least 2 studs of length onto the arm, which can be accommodated, but the 8 tooth gear would hit the bottom and side of the outer arm, rendering it useless.

My other option is to use a pneumatic setup, as the hose can be partially tucked into the notch in the side of the gear rack elements, and fold back on itself as the arm retracts (much like the real thing). Unfortunately, I don’t have any 47225 cylinders, which would be optimal in this situation, I only own the pneumatic components included in the 42043 Arocs, which are either too long, or too small to serve any functional purpose.

Both of these methods have their pros and cons, the pneumatic setup definitely being the easier of the two, but unfortunately it isn’t as accurate or as powerful as a linear actuator.

Any and all thoughts and ideas are welcome and wanted, especially designs.

Also, does anyone know when Brickshelf will be allowed people to create new accounts again? It says “currently disabled” beside the Create New Profile button.

[Jurss]

That axle is moving, an then "hanging out" (don't know correct description)?

Maybe create some WIP topic for this?

Why not use bricksafe then, if brickshelf is not available?

[Hrafn]

How do you approach optimizing structure?  I have a working prototype for a steering subassembly but it needs to be stiffer and I don't know the best way to approach redesigning it.  Do you use digital tools?  Which ones?

 

[Keegan Pilling]

1 hour ago, Hrafn said:

How do you approach optimizing structure?  I have a working prototype for a steering subassembly but it needs to be stiffer and I don't know the best way to approach redesigning it.  Do you use digital tools?  Which ones?

 

I just keep redesigning a component until it check all the boxes of what it’s going to be required to stand up to (fwd-bwd strain, left-right slop, not bending under torque, and the ability to function under the vehicles/loads weight without bending or flexing. I would recommend making a mental (or physical) list of the forces you want your component to stand up to and taking all of the points into consideration every time you add a part.

Also, if you’re using lift arms (Technic beams) I would recommend connecting them with friction (black) rivets, rather than the frictionless as they have less play.

[Andman]

5 hours ago, Hrafn said:

How do you approach optimizing structure?  I have a working prototype for a steering subassembly but it needs to be stiffer and I don't know the best way to approach redesigning it.  Do you use digital tools?  Which ones?

 

Or post it here and ask for suggestions!

[Dr_Chronos]

Please Excuse the hasty mock up, I'm trying to build a fire-spewing dragon. I'm concerned with improving how the twisty rod is pushed through. The best solution to me seemed to be a scissor lift. I figure that it will need to depend on the structure to travel straight, but I'm wondering how to have both sides of the lift move at the same time and if there is a better way to apply force that will give more torque.  I am not good at designing scissor lifts so I would appreciate any pointers. 

Here's a crude sketch for what I'm trying to do. Ideally I'd like the function to activate by squeezing the sides of the body. Other than the above method where some beams rotate to activate it, I thought about having the each of the sides push the opposite side's scissor lift beams out so that it compresses. But I don't know how I could do that without making it difficult to secure it or make both sides move equally.

[Hrafn]

1 hour ago, Dr_Chronos said:

Please Excuse the hasty mock up, I'm trying to build a fire-spewing dragon.

Perhaps the best first line I have read on a post here.

How attached are you to using the twisty pole?  I take it the pole, fire, and actuating mechanism have to stay inside the dragon when it is not shooting fire?  Is this to be a manual or motorized model?

[Dr_Chronos]

On 8/6/2021 at 11:53 PM, Hrafn said:

How attached are you to using the twisty pole?  I take it the pole, fire, and actuating mechanism have to stay inside the dragon when it is not shooting fire?  Is this to be a manual or motorized model?

My plan is to have the fire rotate as it telescopes out of the mouth. I thought about a couple ways to do it, but the simplest way I think would be to use the twisty pole. I'm pretty attached to it. 

Everything would be inside the dragon when it is not shooting fire. The flames would be inside the head while the pole and mechanism would be in the body.

I want it to be manual powered but I'm thinking about making it a windup. For that I would use a mini turntable gear powered by some windup motor or mechanism to turn the fire + pole, and the pole would then force the telescoping fire to extend. That way is a bit more complicated though so I'm not leaning that way.