Super-Sizing a LEGO Bulldozer with 3D Printing

When Matt Denton, engineer, maker, droid builder, and 3D printing enthusiast was a child, he was, like many of his peers, a huge fan of LEGO’s Technic building kits. The kits were first released in the late 1970s and were designed to be more challenging and technical than regular LEGOs, teaching kids (and adults) to build miniature vehicles with functional and moving parts. Denton – also probably like many of his peers – is still a fan of the kits today. Unlike most of his peers, however, he has taken them a step further, super-sizing them using the original instructions with some 3D printed parts.

Denton has already made a go-kart (and motorized that go-kart) as well as a forklift using the kits and his LulzBot 3D printers, with some help from his young nephew. Now he has released another video showing his latest project – a bulldozer.

“This was the second kit that I ever got, and possibly my most favorite,” Denton said.

The kit came with 372 parts, which is a lot to 3D print, especially on a large scale. Denton and his nephew were up to the task, however, as always. Some of the parts required a bit of extra effort; the tracks, in particular, needed metal pins to add strength to them. He used a 24-mm drill bit to clear out the holes in the 3D printed Legos so that the axles would run through them more smoothly.

“The gearboxes did require some additional tinkering just to get them to run smoothly,” he added.

There was a bit of an issue with the bucket-lifting mechanism on the front of the bulldozer – namely, it was too heavy to lift properly. Denton said he might take a closer look at the mechanism to see if he can find a way to make it work more smoothly – and knowing him, he’ll likely find a way. He also decided to try motorizing the bulldozer. The motors he created for the go-kart were a little too big, so he designed some smaller ones – and almost sent the bulldozer rocketing right off the table. The motors definitely worked.

“I think that’s a pretty successful build, and definitely the most difficult so far,” Denton concluded. “We need to sort of look into getting (the bucket mechanism) working a bit better, and making it remote controlled, because the motors worked really well and I think it’d be really good fun to make a radio controlled version.”

Denton’s nephew also suggested giving the bulldozer off-road capabilities.

“One step at a time,” Denton responded.

The bulldozer took 600 hours to 3D print, using LulzBot TAZ 5, TAZ 6 and Mini 3D printers with Flexystruders and MOARstruders. For material, Denton used Premium PLA from 3DFilaPrint and PolyLite PLA from Polymaker.

Denton’s projects are an excellent example of the capabilities of 3D printing – and they also confirm that you never really outgrow LEGOs, you just make them bigger.

If you’d like to try making your own giant LEGO bulldozer, the files will soon be available on Denton’s Thingiverse account.

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