90 ton 1/14 metal excavator scratch build w/embedded PC

[SteinHDan]

Hi Marquez81,


Thanks!

I'm not sure if I understood you correctly, but if you ask if I plan to do the same as this for the rest of the components of the excavator, then the answer is yes. (even if I'm in that phase of the project where it dawns on you just how much work that is left... ;-). Just got to make sure to have a little bit of progress every day, and it will get done eventually. )


Best regards,
Stein :-)

[SteinHDan]

I started work on the upper frame and base:



All the parts are milled from 6mm 6082 aluminum.

The base is 10 mm less wide on all sides than the finished base will be. I'm planning on 3D printing parts that will go down to the same depth as this base plate, to try to avoid having to paint so much.




The upper frame is put together with two middle parts perpendicular to each other and that slot into the sides. This gives the upper frame support in all directions. The sides bolt together with two 110 mm long M6 hex bolts (not shown in the pictures).












The uper frame then goes onto the base. It will be fixed in place with an 20 x 20 x 2 mm aluminum angle bar, 310 mm long (not shown in the pictures).

[SteinHDan]

Stepping back a few steps and mounting the new slip ring, adding PTFE protective tubing to the drive motor wires and mounting the angle bars that hold the upper structure in place.

The PTFE teflon tubing is this one:
- http://www.ebay.com/itm/111392849268

[SteinHDan]

Mounting the boom

I'm going to try to use electric gear motors first. If that doesn't work out, I'll make the excavator hydraulic instead.

I'm using some quite powerful gear motors for all of the joints.
Ebay link:
- http://www.ebay.com/itm/221515025957

These are 10 rpm 320 kg / cm stall torque motors. Two in parallel should produce 640 kg / cm.




The two motors mount to the upper structure with 8 M5 countersunk bolts.






The boom itself is constructed with two milled 6mm aluminum profiles. At the end, another gear motor is mounted with another 8 M5 countersunk bolts.

I bought the hubs on aliexpress:
- http://www.aliexpress.com/item/10mm-...922964248.html












I'm using gas springs where the hydraulic cylinders would normally go.
The gas springs functions in many interesting ways in this configuration:
- Equalize the weight of the arm, so that the gear motor only have to lift the payload
- Dampen sudden movements and protect the gear motor
- A sound that is similar to a hydraulic cylinder
- Visually resembles a hydraulic cylinder.




Item links:
- Gas springs: http://www.ebay.com/itm/181788326018
- Clevis: http://www.ebay.com/itm/161559757356
- Rod eyelet: http://www.ebay.com/itm/5mm-Female-T...-/181888111312

[SteinHDan]

The stick consists of these parts:
- Sides in 3mm aluminum
- Hubs in 12mm aluminum
- Gear motor (similar to the previous ones)



Again, the gear motor is mounted with 8 M5 countersunk bolts.






Mounting the stick onto the boom:

[SteinHDan]

The bucket linkage is milled from 12mm aluminum. The gear motor is driving the bucket through these links, so they need to be strong.

The pins are M8 x 80mm pins bought here:
- http://www.ebay.co.uk/itm/291511678072

[SteinHDan]

I've tried to construct a bucket without welding. It looks pretty ok and feels strong even if I've just printed it in ABS for now. I'll mill these parts in 10mm aluminum shortly. But I just had to print one to see how it fit. I think it's a little wide, so I believe I will make it a 5-teeth one instead of a 6-teeth one.

The construction uses a center slice that is tapped with M3 thread. All the other parts just have a 3.18mm hole in them.

10 M3 60mm long countersunk bolts are then inserted from each side, and bolt into the threaded center slice.

Bolts are added to odd-number holes on the one side and even-number holes on the other side.

The good thing about this approach, is that the width of the bucket can easily be changed. It would also be super simple to create a sifting bucket.

















Borrowing the cab from a Bruder CAT 320 1/14 to see how it will look with a cab on: