After doing a few alternative builds on technics sets I have been thinking about a scratch build in technics of something for a while. I am a sucker for cranes and have a desire to build a decent model out of metal but lack the justifications since those kits are upwards of $2k. I picked up a second hand lego set 42042 which was their attempt at a crawler crane many years ago. Of course technics have improved lots since then and I only bought this for the ideas.
It didn't look great.
TLDR:
I made a crawler crane from lego. Unsalted roasted cashew for scale.
Waiting on some lego parts from Europe and some black braid from China to finish the little details and colour coordination but this is virtually complete. Many many iterations including the original design was without a luffing fly so it would sit on my desk. Curiosity got the better of me and I put some bits together and gave it a go. The thing was hopelessly unstable laterally so I took it off. Then I thought about how to stiffen it up under the main deck and so now it has a luffing fly and stands over 1.9m tall. This will not fit on my desk.
Started by measuring the width of the lego track and then comparing it with various crawler cranes to see if a scale (ish) build was possible. I wanted something in the 600 - 1,000t class.
As these cranes are much the same irrespective of manufacturer I settled on Liebherr as they have some good information available as downloads. At 1:50 the tracks were 2m wide which drops the model firmly in the LR1700, 1750, 1800 sizing and if a bit smaller scale then the larger cranes. Checked the track lengths and heights and various other dimensions and made up a spreadsheet. The LR1750 was damned close.
As it is now:
Non lego bits: The winch cable is 40kg fishing braid, accurate for scale at 0.55mm for the 28mm rope. The rams head hook is from a plastic model which was edited to fit into a lego piece to form the main 350t hook. And I will be making up some pulleys because the lego ones are either too big in diameter or too small or too wide.
Non scale bits: The fly, boom, mast and arm elements are way too big. They should only be about 2 to 3mm in diameter. This though was the only option with enough strength to support itself and well that was how the lego kit was done albeit at a larger scale. The pennants are too big but as these are a standard lego 16 long connector I went with those. Plus I had a few and they look right next to the oversized boom elements...
Otherwise it is all standard lego technics pieces and within parts of a mm for correct scale sizing. As it sits it represents the crane with 70m of main, 28m of fly at 30m radius. Good for 201t.
And Bob the minion fits in the cab. Just. He is a big minion at 1:50, over 2m tall. He has all the relevant tickets but isn't driving because at the moment he is doing his MIB impersonation and is atop the Saturn V lego model.
What it should look like.
How many hours? Lots. How much. At least 2. Could it be motorised? Absolutely, the winches are all connected to the right bits and there is room for a couple of motors and gearbox in the carbody. Running axles and gears from that would be simple enough though it will impact on how it looks. As for the drive units plenty of room under the main frame for the motors and battery box. Just like the real deal.
The boom and mast and fly will be yellow and the odd coloured bits will get changed out when the parts arrive. Then it will sit on the floor in my study and collect dust.
A couple of sadly relevant things. I could have saved $200 and built this without buying the used model because by the time I am finished all I will be using are the tracks and a few connectors. Lego have sort of announced that they will release their version of the LR13000 late this year. Bugger. It is expected to cost around $1k here though.