I don’t own the set, but I was wondering if I could build it with the parts I already had. So the challenge was to build model 42049, the mine loader, with only parts from set 42009. I think I did a great job.
Most parts I needed I had, albeit in a different color, or I could simply replace it with a part that could make exactly the same conections. The real challenge was making the gripper work without the track rods to convey rotating motion between perpendicular planes. But more on that later. First let’s have a look at the original model:
Changes to the body
Let me start with the body of the vehicle. On the back segment I replaced the beam I-frame with a 3×3 T-beam (A) and a 2m beam (B). Together they perform the same function. The turntable used in set 42049 slightly differs from the one I have in my donor set 42009. The geared connection between it and the double connical wheel Z12 will not work under a 90 degree angle. I solved it by not gearing under an angle at all and instead use two small gears in the same plane to let the axle drive the steering (C). The “Technic Panel Curved and Bent 6 x 3”, that basicly are the eye candy of the set and form the wheel casings for the front wheels, I replaced with the 3×7 panels from my donor set (D).
On the back end, near the engine, there is an antenna (E) and an exhaust pipe (F). In the original set they are both nice molded lego parts. However I had to replace them with something different and some imagination.
The robust bumper section uses two of the aforementioned “Technic Panel Curved and Bent 6 x 3”. I build my own panel from one 3×5 and two 2×4 90 degree angle beams.It obviously does not look as nice as the original design.
The side of the driver’s cabin is left quite open in the original design and where my model lacks the right wheel casing (D) it also has some improvement. I think that the use of the 3×5 panel from my donor set to form the bottom half of the drivers cabin (H) is visually a lot more attractive than envisioned by the lego designer. I also put one on the right side of the vehicle. Just because I could.
As you can see from the bottom up there are three universal joints needed. My donor set only has two. I solved this by making connection 3 a geared connection. This works just fine, but a universal joint is the better solution.
I redesigned the gripper quite a bit. Below on the left is the original gripper from set 42029. The essential part I did not have in my donor set was the track rod (K) which allows to convey rotating motion between perpendicular planes. I build upon the original design, using the auger, the z24 gear and two triangles: I turned it 90 degrees along the axle of the auger and mirrored it. Now all the rotating motion to open and close the gripper occurs in the same plane making it easy to use a cross axle and two angle elements (L) to replace the track rod. The whole thing fits the same way onto the arm of the mine loader. It is just one ‘hole’ longer and quite a bit heavier. Nevertheless I am quite pleased with the result.
Adding a linear actuator
Because my donor set 42009 had lots of linear actuators I thought why not improve on the primitive lifting design of the original mine loader and add a linear actuator. After all, in real life it would most certainly be hydrolics. It took me a while to figure it out. I would really have liked to be able to drive the actuator from a wheel on the back of the vehicle. Much like the gripper open and close is operated. It being a low profile articulated vehicle proved not enough room to do a proper job. I settled on wheel on top of the front side to operate the actuator only to find that it was too big and in the way. It was not an improvement at all. So I changed it back to the more pragmatic original design which simply looked better and handled better.