On 9/6/2017 at 5:00 PM, suffocation said:

You'll want a sturdier undercarraige than 8043's, though.

Of course he will. But first of all, he need to learn how  that trick with empty driving ring works.

Indeed

@Mechbuilds -  Once you've cracked the coaxial conundrum, I recommend having a look at the substructure of 42042. It's much lighter than 42055's but still very robust thanks to the use of diagonally placed beams.

  On 9/6/2017 at 5:00 PM, suffocation said:

This ^^^

You'll want a sturdier undercarraige than 8043's, though.

 

As for the gearbox, how many functions would you like to implement and using how many motors?

i'm trying to have one motor on the upper half.. The battery switch directions will move it forward and backward. And flicking a gear switch will change it from drive to steer and then the battery directions will steer it left and right. 
The upper half will be turnable by hand. 

I'm struggling how to implement the mechanism to the bottom half. 


Now when i think about it, i'd like it so i hold the model from the top half and use switches to make the bottom half move.. Rest will be hand cranked manually. 
(Don't have RC parts. Only got one motor and one BB for power functions..)

Edited September 6, 20177 yr by Mechbuilds

This is a very basic setup (you'll need much stronger framework, of course) that gives you seven independent, two-way outputs. Don't cringe at the three 8z gears - they can carry more than enough torque for an excavator.

 

That looks cool. I could make it so the motor powers everything. 

No wonder i was having trouble with my own custom gearbox.. I completely forgot these existed:

Thoughts? It's a gearbox that'll take one input shaft and turn it into two rotations in the same direction or two rotations in the opposite direction (after i attach the differentials to the front end.)
Weakest link is the two gears on the sides which are only connected by a 3 stud length beam. 

So far, the testing has shown that it works perfectly. 
(The three long beams are just there to keep the gear selector in place as i figure out a sturdy way to connect it. )


This is a fun project.
Imagine a car that'll have a gearstick that can only go forward and back a click. Then you have two pedals on the floor. Left pedal will go backward and turn to the left and the right pedal will go forward and turn to the right. 
 

Edited September 7, 20177 yr by Mechbuilds

  On 9/7/2017 at 7:06 AM, Mechbuilds said:

That looks cool. I could make it so the motor powers everything. 

Exactly - one input, seven outputs. You can arrange it to have more or fewer outputs, of course. You could also have the input in the middle and three (two, four, whatever) functions mounted vertically on either side, like this (sorry about the hideous pics):

 

Edited September 7, 20177 yr by suffocation

I'm giving up on this project because the gearbox gets so low that it'll lift the tracks in the air. I'm going to switch from an excavator into making a landrider style tank. 
After i get the hang of making proper gearboxes, i'll retry the excavator once more. 

But it was a great learning curve. I just need to rethink this thing. 
Can't wait until i get my package in the mail. Expecting differentials and whole bunch of gears. 

I'm back in business. I got the package in the mail and got my differentials. 
Found a flat gearbox design from google search that i copied and modified a little.
Pictures coming soon. 

I'm currently having two axles on top of eachother, one stud away from eachother.. Lower one for drive and upper one for steering. 

Can i get two functions trough the turntable by using the new differential?


EDIT:

The reason why i'm asking is because i only have the 42055 set parts to use. And i'm beginning to think that it's impossible to get drive and steering trough one turntable with these parts.
I think i'll just have to order the turn table 2 function parts from brickowl.. 
 

Edited September 11, 20177 yr by Mechbuilds

42055 already had all the parts you needed to get two functions through a turntable. One thing that might not be clear from the pictures is that the driving ring ( ) going through the turntable must be without the driving ring connector ( ). This way the driving ring and clutch gears spin freely around the axle, giving you two independent coaxial functions. Of course, you can replace the driving ring and clutch gears with a 4L differential - the end result is more or less the same.

 

Edited September 12, 20177 yr by suffocation

And i'm back with an update. I haven't given up on this project just yet. 
Here guys, have a fresh new set of pictures. Gearbox for bottom end done!









It has a cool looking tank storage in the back in a secret compartment that opens. 


Thinking about making a bucket wheel excavator style scale "massive excavator" with a control room that can be moved up, down, forward ect... 
Big arm that can have attachable attachments like twin buckets or a pinching claw. Going to push the battery back to the rear and a large motor paired with a large gearbox to control everything. 
So my idea is to make an opening that has two or three gear sticks so i can control the arm with it. 
Like the first gear stick is drive /steer and the second one is arm up/down and arm extend/contract and third stick for attachment movement A and B. 


It works like this:
Selecting one gear will have two functions by playing with battery rotation direction. 

So drive gear will have forward and reverse drives. And the steer gear will have left and right. 




Any tips how to make the most compact extra large engine gearbox setting that i can directly attach to the turntable on top? 
Does lego have an excavator that has the motor manouvering the arm with linear actuators? I should check the instructions... I currently have three linear actuators and i plan to have full arm movement with only those. (not putting two at the bottom)





Also thanks in advance for helping a newbie out. I'm slowly getting the hang of building technic. I just need to stop thinking 2d and learn how to think 3d. 

Look at 8043, just swap the two LA at bottom for one.