It has never been easier to build a complete Great Ball Contraption (GBC) loop yourself! The GBC 51 Gravel Works features multiple modules which brings GBC Balls from one side to the other. The GBC can be used as a self contained loop or participate in a GBC layout.

This GBC is entirely built using only parts from the LEGO 42131 CAT D11 Bulldozer set and can be referred to as Alternate Build of the 42131. This GBC makes sure you master the GBC building techniques and tricks so that you eventually also can build your own GBCs. By default the whole machine is powered by 3 motors which come with the LEGO set.

Only for the toughest jobs!

There is so much going on here and GBC Balls are rolling everywhere in the GBC 51 Gravel Works. Featuring 6 modules and many paths to travel this GBC has a bit of everything.

One of our new models on the GBC 51 Gravel Works is the Wave Machine. As the name implies a wave will be generated pushing the GBC Balls forward. It is build using the big sloped panels which create this zig zag pattern over the 7 individual planes. As the planes a very wide, it can handle a lot of GBC Balls at the same time. Hence why it will also be used to drop the big tilt plate on it. The complete machine is driven by a long axle at the bottom which in turn will drive all the 6 levers in sync. With 7 colorful sections it is one of the biggest modules we have yet created and it is so much fun to watch in action. A big upsell is the height gain where the GBC Balls will slightly roll uphill 7 studs higher when they reach the end. Always important for most GBC modules.

Once the GBC Balls exit the Wave Machine on their own pace they will roll onto the loading stage of the Vertical Lift Platform. Many balls can be on hold here waiting for the platform to lower and pick them up. Another motor will lower the platform and pick up the GBC Balls. After a few seconds the platform raises again automatically to the top where the GBC Balls will be dropped onto the Dual Conveyor Module. All timing is done in software as this opens up so many possibilities where users can easily change the behavior and get more interaction.

Using the new yellow conveyor links we knew the Dual Conveyor Module would bring the classic module from the GBC 15 Mining Plant to a new level. With the black beams attached to the belt, this module can process a lot more GBC Balls. By default the supporting legs are secured in place and the GBC Balls will travel a 23 cm (9 inch) upwards. However if you ever decide to mix things up, and use the module as a standalone, you can even raise and lower the module by changing the linear actuators used in the support structure.

Once at the top 33 cm (13 inch), the GBC Ball will roll downwards in multiple routes. A flip flop mechanism makes sure the GBC Balls are evenly distributed among the 2 paths. The left path will directly feed the GBC Balls onto the Wave Machine so this module will never run dry. The right path takes the GBC Balls over the zig zag path where also 2 GBC Funnels can optionally be installed. If you want to have that extra epic-nes you can get our GBC Funnel XL – Left and our GBC Funnel Gravity Well – Right. When installed it takes a good 25 seconds, if not longer, for the GBC Balls to roll downwards onto the Tilting Plate. Note that the GBC Funnels are completely optional and the GBC can also work without them.

We always love it when at certain moments in the GBC a lot of GBC Balls simultaneously enter the modules. That is where the Tilting Plate comes in. Don’t you also like the tension there is of when the plate will tilt and drop the GBC Balls? In the past we have also include this into our GBC 41 Power Pit Mania where the big shovel part of the LEGO 42100 set acts as the bucket. The Tilting Plate can hold just a little bit over 40 GBC Balls after which it will drop. It is important that the next module in line can handle these batches of GBC Balls. Likewise it is important that the GBC Balls find a way to get separate again in smaller bulks. This brings us back to the Wave Machine which can solve both problems.

Fun Fact

Once we got the Wave Machine working we thought it would be cool drop a big batch of GBC Balls at once on the wave to see what happens. This turned out to be very intriguing to watch but it had one problem. In the time that all the GBC Balls left the Wave Machine it takes some time to happen again. That it why we figured to add a second path which drops GBC Balls on a more regular base on the Wave Machine as well. The Flip Flop is the perfect mechanism for the job and splits the ball path in 2 separate routes. In this way the GBC 51 Gravel Works will always get your attention somewhere.

Work Together – Enhance building skills

The whole GBC is split into different parts/modules which are assembled together during the build. Ideal for working in groups as each builder can work on a sub assembly and later click everything together. Because of this construction and flexibility it is also always possible to separate the modules again and make your own unique configuration or use modules as separate machines.

A really cool feature of the GBC 51 Gravel Works is its ability to convert with ease into a GBC Layout Module. You can simply add your other GBC Modules to the sides and drop the GBC Balls on the Wave Machine. There are many options for the GBC Balls to exit the GBC 51 Gravel Works. In this way you can easily connect this GBC to all our other GBCs to make the loop even bigger. More information in the building instructions. Clean and simple: Convert with ease.

It is possible to move the whole structure at once when you hold it right. However, when moving the GBC, we advise to place the GBC on a solid plate or to disassemble the GBC in separate modules again. Footprint of the GBC 51 Gravel Works: 85 cm (34 inch) by 54 cm (21 inch).

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GBC Funnels

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