March 29, 2013 Leave a comment
We all have our favorite LEGO sets. Then we also have sets that we think were pretty cool. Set 6352 from 1991, the Cargomaster Crane was one of these sets for me. It was a set simple set, it was perfect for a growing child. Small, playable, yellow, and it could lift things.
Recently, I decided I wanted to make a little Technic crane. I researched a number of designs, none of which really struck me as something I wanted to pursue. I kept coming back to 6352. Why not make a crane like that? Perfect. I wanted it to be a nice homage to this classic set. I was going to make is just like 6352. Double the size, same shape, complete with containor and tractor, and of course a driver. The full gallery may be found here.
I stared with a simple frame built for the outriggers at both ends. I knew I was not going to be able to add a more complex outrigger system at this scale that would reflect the original crane, so I made manual outrigigers just like the original. I added two steering axles so the crane could drive to and from the site, then I placed a turntable right on top of the chassis.
As I started the superstructure, it become very clear very early, that having an offset crane boom like the original model, was not going to be a good idea. My model was going to look off, and the balance of the offset boom was going to make stability, both for the superstructure, and the crane as a whole, a problem. I knew the size of the boom, and decided to place it in the center of the crane. I then placed the cabin, and set it up for the little technic figure.
The boom was relatively simple; two stage, and 23 studs long. The outside was simple and straightforward, meant to be sturdy and strong. The pivot was at the rear on top of the winch, and the elevation ram was connected forward under the front of the boom. There was a simple worm gear under the front that would drive a set of gear racks, to drive the inner boom. The inner boom would hold the final boom which was only a series of plates. Each stage was connect by a two cables to make sure all the booms moved together in unison. It worked well, even under load, as you can see in the video.
The model worked well, and had perfect balance. The simple boom extension worked well, as did the winch. The outriggers gave appropriate stability through all positions. And it looked very similar to the original model, even with the little tractor.