
Mobile Crane (42108)
Another Brick Club member has built the Mobile Crane (42108). This one goes out regularly, which makes sense. It is a proper yellow mobile crane at a sensible size: 1,292 pieces, eight wheels with steering on all four axles, and a boom that raises and extends until the whole thing stands 78 cm tall.
Everything is worked by hand. Separate knobs on the sides of the superstructure raise the boom, extend it and wind the hook, and two ratchets with red release levers stop the boom sliding back in and the hook dropping. The superstructure swings a full circle on a big turntable, and the outriggers flip out one at a time and click into place, lifting the tyres off the ground.

The Mobile Crane (42108) came out in 2020 and is a different set from the much bigger Mobile Crane MK II (42009), which has 2,606 pieces. There is no gearbox or piston engine in the 42108; the pieces go into the crane itself. One Brickset reviewer found the boom slow to lift from flat, and it eases once the boom is a little higher.
What makes this one worth building
The steering is worked from the two orange beacons on top of the cab and turns all four axles. It gets heavier towards full lock, so stop when it stops turning freely rather than forcing it. The boom is long even before the last panels go on, and the grey winch string looks like real steel cable.
Go steadily on the steering racks early in the build. The Brickset reviewer found they rely on a little natural play between the pieces, so check they move freely before the chassis closes up round them.
The useful thing about a second or third member build is that it stops the post feeling like a one-off. Different builders notice different parts of the same kit, and the photos always come out slightly differently.
That is why I keep publishing repeat builds when they come in. If a kit keeps going out, that tells me something about the library. If members keep sending photos, that tells me even more.
Rent the Mobile Crane (42108)
A monthly subscription gets you one Technic kit at a time. When you are done, send it back and we send the next one. Free postage both ways.