8×8 Ball / Roller Bearing
Idea for a ball bearing or a roller bearing which can be built using the new Lego round tiles.
Lego has recently released a 21130 The Neither Railway set featuring a number of new pieces, especially the 2×2 and 4×4 round corner tiles which form a perfect 1 stud wide gap between them when put together. As soon as I saw them, I wanted to building a ball or roller bearing using them, and in the end I’ve done both. Instructions for both variants are provided in the video below.
The entire mechanism is pretty simple and comes in two variants, one using Lego balls, the other using small wheels on pins instead. The difference is that the ball bearing has much less friction but requires balls, which are less common and more expensive than wheels and pins, and it’s also a taller and a little less stable. The roller bearing, on the other hand, is cheap to build and more compact but at the cost of significantly increased friction.
I have though of this mechanism mostly as an alternative to Lego turntables – something that could be used e.g. to rotate heavy display models for long periods of time with minimum friction and minimum parts wear. It’s therefore best suited to operate in horizontal position – using it vertically would require some sort of brace that would prevent it from splitting open. It seems too large and not rigid enough to be used e.g. to mount wheels in vehicles. It can, however, be driven, either by simply using a horizontal wheel, as shown in the video, or by using a vertical axle. Because the 4×4 round bricks used in the center of upper and lower half of the bearing come in two variants: with axle hole and with pin hole, it’s perfectly possible to drive the bearing’s upper half from below. It requires a vertical axle that goes into a 4×4 round brick with an axle hole in the bearing’s upper half, then goes through a 4×4 brick with a pin hole in the lower half (so it can rotate freely inside it) and connects to a motor or some other kind of a driving mechanism.
Note that the ball bearing in the video uses Lego Zamor spheres with a diameter of 2 studs. It’s perfectly possible to use Lego soccer balls popular in GBC creations, whose diameter is 1.75 studs. This will only result in a slight reduction of the bearing’s height.
