Mechanical Beaver

Canada Day is coming up and this year is a pretty special one, as it marks the 150th anniversary of our country’s confederation. The entire country is celebrating, with many ‘Canada 150’ events going on throughout the year. In fact, LEGO builders from around the country have already joined the celebration by building many Canadian themed models, which can be found at the Canada Builds 150 website, with more being posted throughout the year.

I thought it would be an interesting challenge to build a mechanical LEGO sculpture of our national animal, the cute and industrious beaver. You can watch the video to see it in action, along with an explanation of how it works. Building instructions and more details are below.

It’s a pretty simple mechanism, consisting of a single drive shaft with a cam that slaps the tail and a crank connected to a piston that opens and closes the teeth.


Building Guide

PDF File

Digital Model Files

LDraw File

Additional Resources

Parts List


You can operate it with a hand crank inserted into the side of the body, or by using a Power Functions M-Motor. The slapping of the tail is pretty loud, especially on a hard surface. I would recommend putting something soft under the tail to dampen it unless you are intentionally trying to annoy everyone nearby. If you connect a motor to it, I would also recommend either gearing down the motor, or using the Speed Remote/IR receiver to control the speed of the motor (or the rechargeable battery box). Directly driving it with the motor at full speed can result in some pretty spectacular tail slapping!

I had a lot of fun building this model, and Kristal and I are working on a couple of other Canadian themed models to continue the Canada 150 celebration.

2 thoughts on “Mechanical Beaver

    • Well, I don’t actually sell kits, so I can’t really help you. I guess you’d have to order the parts you need from Bricklink and hope they arrive quickly.

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