by sun yun

Building joints is probably one of the most difficult aspects of building Lego mecha. Factors such as mass, friction, leverage and a host of other variables all come into play. The directions and possibilities are as endless as the number of elements in the Lego system of parts. This articles uses some "inventive" methods in overcoming the restrictions and shortcomings of current parts. Some modification to parts and use of non-Lego elements maybe necessary.

Plastic Wrap
Uses: Rotational Joints
Technic pegs are great for rotational articulation but lack enough friction to bear any weight. By applying two or three layers of plastic wrap over the peg, friction is instantly added to the joint. This method is easily reversible and allows you to control the exact amount of friction depending on how many layers you use.

Brick Hinge with Flex Tubing
Uses: Major joints; knees, elbows
Although the brick hinge is the big brother of the plate hinge, it lacks it's little brothers friction. Christopher Snead has developed an approach where friction is increased dramatically by inserting a technic flex hose between the two halves of the hinge brick and them triming the excess hose off. The drawback of this method is that the process cannot be reversed.

Plate Hinge with Wire
Uses: Major joints; knees, elbows
Another Christopher Snead solution, this approach uses thin gauge wire to increase friction in between the two halves of the plate hinge. Once again by combining multiple hinges with this modification you can create a very strong tensioned joint.

Technic Liftarm with cut Ball and Axel
Uses: Multiaxis joints; shoulders, hips ankles
This is a technique I've used since the Throwbot/Bionicle liftarms were first introduced. When I first saw these parts I loved the smooth tensioned movement but was put off by all the unecessary details of the part. My adaptation of the part requires cutting out the central part of the liftarm. This part yields two great ball joints.

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