I prepared all the drawings (about 380) of the various parts to be made (approximately 660) and the 116 files to be used for all the parts to be produced by laser cutting. At the same time I examined what were the most difficult pieces to make and looked for new technologies that would allow me to solve various problems in the best way possible, consistent with the depth of my pocket.

The first part examined was the links of the tracks, not because of the difficulty of making them, but for the fact  as many as 56 pieces were needed, and I know I wanted to be sure how they would perform. The use of a 3D printer to make four links in ABS plastics and the production of a rudimentary wheel drive allowed me to check things.

Here are some photos:

My research eventually led me to come across the SLM technology (Selective Laser Melting).

It’s a process that starts with a 3D drawing. The workpiece is made of metal, by spreading a thin layer of steel dust and fusing the particles with laser points corresponding to the section of the piece. The whole component is iterated layer by layer until completion.

The layer of powder can have a minimum thickness of 0.03mm (0.05mm in my case).

It is possible to create pieces of incredible complexity, impossible with conventional technologies. The finished piece has mechanical properties equal to a similar piece made from solid metal. These particuclar pieces were made from stainless steel AISI 316.

The following photos show the pieces as they come from the SLM process, and before finishing processes such as opening out the holes, etc.)

Let's start with the bucket:

Below is an image of the cross section of a piece used for tests, which clearly shows the solid nature of metal from the process of laser fusion:

The bucket is provided with two side attachments for the support:

The C-shaped support of the bucket (Bail Dipper) has a complex shape and, in addition, to make it like the original, it should be hollow.

No problem with this technology, in the close up shot you can see clearly that the inside is hollow:

The next piece is the pulley support.  The axis of the pulley is rotated with respect to the axis of coupling to the Dipper Bail To ensure that the steel rope that runs on the head of the boom can use two spaced pulleys.

Finally, it is the operator’s seat, also produced by SLM.

In this period I also proceeded with the laser cut pieces (more than 200) that made up the assembly thus far designed and started assembling the parts needed for the three steam engines. In addition, I also started to make all the other parts; it's long and exacting work but I wanted to try the engines before proceeding with the rest of the project.

Part one   part two   part three   part four   part five  part six  part seven  Part eight

part nine   part ten   part eleven  part twelve  Conclusion

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Editor - David Carpenter