896gerard

I understand. You are right. I was assuming the general idea of 'making an active controlled differential'. The implementation of this idea is different for our models. I was not trying to take the price. I think you have made a brilliant and good-looking model around an original technical principle. That's a good thing.

2016.

I find the fact that all motors have an encoder now very interesting. No more need for servo's !!! So no expensive steering servo, but just a regular motor, this makes them cheaper too. On the other hand, it might not stimulate designer creativity. With 'the old motors', it was always an issue to gear it down or to create a repeating mechanism when a linear movement was needed. Now you can simply program the movement and do the job with very little oldschool mechanics. That opens the road for big clumsy motor-infested MOCs without any space for mechanics (the motors are not getting any smaller). Secondly, I think TLG should think of a remote control with physical levers. A Lego Technic race car with high speed is uncontrollable from a touchscreen because there's no feedback from any knob. Looking on a screen where the slider is while also tracking a very fast object doesn't work.

Regarding this debate, I have another question. (Still for the ultimate model I was talking about) I need a crane outtrigger with an extension of 100 millimetres, two studs wide and strong enough for a 2 kg model. The biggest concern to build this with Lego is that there are no gear racks long enough and small enough to fit within a two studs wide outtrigger. Lego Technic has seen this problem and come up with a part, but the extension is too small for my application. Also, the 18940 part requires an axle leading to the top of it for a powered extension. A a very visible axle does not help with getting a nice visually appealing scale model. Therefore, I decided to take up the gauntlet and start desiging this part for myself. The tried-and-tested prototype is below. This structure can support 10 kgs of weight (tested) and allows a very smooth extension of >100 mm. A big advantage of designing parts myself is that I can adjust the size anytime I want. And this is the time where I need some opinion on this. Is there a Technic way of doing this? Maybe I didn't think of something. I want to exhaust all options before using a non-Technic part inside a Technic model.

I agree, honesty is very important here. That's why I don't want to sell these parts: I have a purist heart and know myself to only use these pieces when nothing else works and know myself to always communicate the use of custom parts. Other builders might not have the same intentions and use the parts only because it needs a lower skill level. That is not my goal.

That's why I posed it as a debate in the first place. Again, it depends on the goal that needs to be achieved with your MOC. For most MOCs, the goal is 'use only Lego pieces'. But why is (for example) the S-brick/ or alternatives so broadly adopted among Technic builders? Because it is a way better solution than any solution that Lego has come up with. I'm currently building a model for which the goal 'use only Lego pieces' is simply not good enough. The concept of many small pieces to build a working scale model is very strong. Lego pieces have also a very high quality and finish, much better than any 3D printed part. But Lego Technic parts have their limits. And that's why I (a builder who normally finds purity so important) for one single time choose to make a MOC that uses the 'use only Lego pieces'-spirit for 95% of its parts and use much better parts for the remaining 5%. This design philosophy does not disprove, but enforce the Lego Technic platform, as it shows how a very strong concept deserve specific parts that are engineered with much better specifications. It is like using non-Lego wheels for offroaders or a custom machined steel turntable for very heavy cranes. Other builders do that. Do they do that because they are non-purists? No. The rest of their machines is mostly impeccably engineered to use 100% Lego parts. They choose it because it lets their machine shine. And shine is what we so hardly need, because other adults (from 'the real world') don't know a thing about Lego Technic building and about parts purity and the lot. They are driven by amazement only, which is not linked to parts purity at all. There are much more adults who admire engineering over parts purity. I have that experience in my talks to some companies around me that are convinced of the Lego platform and asked for models!

Dear readers, For a new project that started a while back (about a year ago), I was investigating a certain track configuration for a tracked vehicle. It pointed out that I needed a lot of ground clearance from the track wheel, but the track wheel could not be two studs wide: the tracked vehicle is only 15 studs wide and a lots of gears, motors and linkages need to be in between. As you can see, the standard wheel above is two studs wide due to a ring of 1/2 a stud that supports the track. This ring is not always necessary. In fact, the tracks barely even touch this ring under normal driving. A lot of you will recognize the difficulty with this wheel: it protrudes half a stud to both sides. In many designs, the number of horizontal studs is uneven: an M motor, XL motor, frames, differential, everything has an uneven width when measured in studs. This enables a symmetrical design as Lego Technic has no beams with even lengths (only 3, 5, 7, 9 ..). That's why many Technic designs of this day are an uneven number of studs wide. This is in contrary to the olden days, where all Technic components and widths were even. Check for example the old style liftarms, differential, frames, motors and even battery boxes. With this theory lesson over, it is easy to see why this track sprocket introduces a problem: when the wheel is mounted in the uneven Technic system (to get a nice symmetrical design with uneven Technic beams), the wheel size is even! So the wheel can not be connected to a liftarm at the place where the axle connects to the wheel. There needs to be a distance of 1 stud to any supporting liftarm. This is mostly done with a bush or a 3L thick liftarm. This also means that to mount this sprocket very strongly, the minimum width of the structure (when fit in an uneven system) is 5 studs. Then I started thinking: how nice would it be if there would be NO distance to any supporting liftarm? In that case, the sprocket has to be only 1 stud thick and the supporting structure is only 3 studs wide. Also, the support ring has to go. This is an enormous space saver when the maximum width of your vehicle is 15 studs.. I decided to draw the part in Solidworks and print it with my own 3D printer. Out of curiosity, I checked GrabCad to check whether someone got the same idea too. To my amazement, somebody had already tried this part, with the internals to be the 40 teeth gear. This is done with a reason. A standard 3D printer is generally very bad at printing axle holes. If you draw the outline of a standard Lego Technic part (that has a nice axle hole) into your 3D printed part, the part will be connected firmly inside the model(nice) while the axle is inserted into a Technic part, so no troubles with cracking plastic will occur. In short, I printed that part. It didn't work. (See image below). It turned out that every 3D printer is a little different. A tiny offset can cause a diameter difference, which then will cause friction, because the track doesn't fit around. The wheel needs to be perfect to make the solution work. That's why I decided to design my own custom sprocket wheel from scratch. This was my first 'from scratch' attempt. As you can see, the pin and axle holes do not have great quality. A revised 3D design is in the image below. As you can see, there is a large hole in the middle. This hole fits two 4185 pulley wheels (shown right) very tight. This means the vehicle is connected to a nice and round axle hole, while the 3D printed part is also fit very well to the vehicle. The sprocket diameter is not arbitrary as the number of 'lobes' is fixed: there are no half lobes, otherwise the wheel won't work.. That means that for the same tracks, a limited number of wheel diameters exist. As you can see, there is a slight ring in the 1 stud wide sprocket wheel, not all track support is gone. The 3D printed results: I was really happy with the quality of this wheel, the drawbacks from 3D printing don't show up and the wheel is very strong and straight. In the image below, is is visible that the tracks fit very smoothly around without additional friction. It is also visible that the wheel is just as wide as two pulley wheels, so one stud. I was so amazed when the 42095 set was launched. There was my not-published-about part, exactly the same size, in a real Technic model! And now there will be 4 DBG ones in the 42100 Liebherr, which will drop the price. There is one 'slight' drawback though. My 3D printed wheel is only one stud wide, needing only a frame of 3 studs wide to support it. The new 42100 sprocket wheel has the 1/2 stud ring protruding out of it on both sides, taking the drawback of the old wheel onto the new wheel. That's a pity. It could have been so nice. Then comes the question: why would you 3D print parts? That's cheating. And I agree. It is cheating. I never do this in my models. You are allowed to check my YouTube. I even built of a 3D printed way of getting three axles through a Lego Technic turntable but never used the solution as I do like pure models. Then, why am I doing it now? Because currently, I'm using Lego Technic as a strong platform for a scale model that requires 100% of the quality of Lego Technic, but cannot do without adding custom parts. Even the most skilled builder cannot work his way round sprocket wheels that don't exist. That's why I see it as an engineering project, and from that prospect, creating your own parts (when all else fails or doesn't exist!!) does not show lack of skill but broadness of view.. Surprisingly, some other minds thought alike and brought a Lego Technic wheel of the same size on the market. Too bad.. Let's start building and stay thinking!

Regarding the new 42095 sprocket: I'm working on a tracked model for which I designed the above sprocket from scratch in SolidWorks. I have printed this wheel already with my own 3D printer. As I was not happy with the printed pin and axle holes from the 3D printer, the method of connecting this wheel is to squeeze two pulley wheels inside the middle cilinder, which is a tiny bit too small. This connection can handle a lot of torque, depending on the used print material. With my design, I also tackle the problem of the wheel being two studs wide. My wheel is one stud wide. This enables a lot of earlier impossible design solutions. I'm very surprised to see my little secret back-room 3D project so soon in a real Lego Technic set

I think the frustration about the non-stacking property will be large to such an extent that third parties like S-brick will come with a solution. The change to non-stackable plugs is a bad idea as they could always be stacked. Lego is about finding out, not about being limited!

Yes, that's why an RHD version would be special. Mirroring the building instructions in your head is quite difficult but some people like it and do it. I'd love to see the result!

Now you mention UK guys, anyone building a right-hand drive version of the Chiron? It would be a challenge to mirror systems but your Chiron would properly stand out..

The outtriggers seem to differ. Is there another 'real crane' with the 42082 outtrigger system? Or did Lego try to save money..

I so understand that! Building is after all what we like doing the most, video editing and photoshop is secondary to the whole thing... I like the way you constructed a color line on the sides, the suspension, and that you didn't save on power (4 XL's). It's a pity that the battery boxes don't deliver more current as the Truck would move smoother and faster.

Hm, I have had no complaints thusfar while 50 have been given away already. The building instructions cover this part extensively but obviously I can't show that to you ;)

You see it when you build it... this was indeed for me personal one of the gems of this MOC. I really like that you reverse engineered and built it. Did you have another crane in mind with the color scheme? Your color scheme looks good! This is indeed very hard to build (but done because of better looks) and I really like your alternative solution.

I also use LDCAD and have experimented with drawing ropes etc. I agree with you on the learning curve. I was at a point where I just stopped to build digital as the invested time was too much. Seems like I need a little more practice..

Thanks. The first production run is 50 sets which have been given away already. The second run is 2 to 4 times larger. I have to redesign the MOC slightly to make parts ordering easier and cheaper. I understand some choices from inside Lego Technic sets now (about not having too many colors of the same part inside a set). However, in this crane, some parts have different colors in a low number. That makes the set more expensive, but it is after all an exclusive set with a production number of only ~200, so it will be rare anyway. Maybe I'm going to use yellow parts for a crane to see how it works out. I myself have built the same crane around 5 times... I think know it almost by heart now.

Thanks! Apart from building a set, I have also done some set production by now. This means drawing a complete 3D model, creating building instructions with LPub, ordering all the parts. If you look at the outtriggers, you can see that the 3x3 thin red liftarm is used 8 times, while it is rare on Bricklink. So if you go to Bricklink now, you can see it has become much rarer. That is just because of this set... The Lego Group doesn't have to order parts everywhere which makes set production cheaper. I reckon they would sell this set for €49,99. This price is based on sets with a similar part count. I really would like to see this converted into a real Lego Technic set, but the fan base on Lego Ideas is not that great for Technic models (and the model is only to by bought by the company of course... ). I really would like to know how TLG building instructions would look like regarding the extending boom mechanism. I found it really hard to instruct how to do it. I'm still looking after a building instructions tool that supports rope in all shapes.

Why did you use 4 L motors instead of 2? Did you target a certain speed?

We drink lots and lots of coffee... no. 1 in the world. (or at least high in the top 10, as this is old research).

I'm amazed that you mention HOF. I thought this was just a small crane that cost me the same time as a much bigger MOC. Anyway, if you really want it up there, then please submit it to the separate HOF Discussion Topic for submitting your wanted HOF models. I feel honored by all positive remarks.

Building Lego Technic creations and posting videos is a common bussiness for every MOC designer. Coming up with small and large inventions and sharing them is a continuing activity that never bores. However, there is one common dream, one ultimate goal that every Lego enthousiast silently dreams about: to design a professional Lego model. Several builders do what is called 'commissioned work'. Building a Lego Technic model and selling whatever it became to a company or private party. In general, Lego Technic custom models are loved by non-Lego enthousiasts because 'it works'. Several years ago, I got the unique chance to do commissioned work because a company CEO's brother accidentially saw my scale model. I first refused to sell my beloved Luctor, but two years later the one metre model was ready I got positive reviews about the looks, but the most comments were: "wow, it really works". Somehow this model must have been leaked inside 'CEO-land', as one year ago I was asked by the Hoeflon company (based in the Netherlands) to build a give-away Lego Technic model, to be used as a business gift. How cool is it to not receive the 32st boring USB drive, but a complete custom Lego Technic model.. The company builds mini cranes that go inside buildings to do heavy lifting. My task was to build a scale model of a machine that is already very compact in real life. As a result, I present a 1:14 scale model of the Hoeflon C6 crane. (please note I'm NOT paid by Hoeflon in any way, the whole story is just about how things happened and to explain the link with reality). The crane is my smallest MOC for a long time. It was really a challenge to fit all the functions inside the cramped body. The functions are: Track widening Boom rising/lowering Boom extension Fly Jib Rotating superstructure Friction winch Self-locking outtriggers Variable angle outtriggers with over 90 degree range These functions happen in a Lego Technic model of a smaller volume than the 9391 Technic crane set. Over the years I had lost some creativity to build small models so this one was a real challenge. I'm happy with the current setup but who knows.. The model is delivered with black or LBG tracks. LBG track links are slightly more expensive and this quickly adds up when 100+ cranes need to be made. To be fair, I find the looks of the 9391 stunning for the low part count. However, as I show in the video, it does not really work as a crane. The above photo shows the comparable sizes of both models. The front view. Please note the relative widht of the tracks: They are each 3L while the vehicle width is 7L. The resulting chassis is one stud in width! To widen the tracks, the crane has a shifting axle system with half bushes as stoppers. The final result is not the strongest system, but the crane at least has the function! The top view shows why this crane is called the 'Spider Crane': the outtriggers can be seen as the legs. The great thing about building such small models is that every part can be seen and every part has its function. There are very few 'unused studs'. This crane has a 3-section boom. In transport shape, this crane is 12 cm high so all of it should be folded. Therefore it looks like a proper mess when folded in. It is a common known fact that Hoeflon cranes will lift their own weight, because one crane should be able to lift another crane into a cellar. Hopes were low for the scale model as it is fully made from plastic Lego pieces. Under these loads, they will simply bend. Using the correct crane position and the winch, I got one crane to lift the other - just. On this small scale, I could not use the same strong structure from the real C6, so it was a nice result that my building resulted in something with the same strenght. The crane in full extended mode. The shape changes dramatically when the boom is unfolded. It reaches a maximum height of 42 cm. This model is meant as a business gift. This box was developed by a third party and it looks great. It is just big enough to contain the 425 parts and the A5-sized building instructions. I spent really hours drawing a 3D model and creating building instructions with lPub. By doing it yourselves, it becomes clear how much time goes into it.. The agreement with Hoeflon was: me delivering the PDF, Hoeflon doing the printing. I'm really pleased with the end result. To conclude, this MOC shows that you don't need a lot of parts to build a fun Technic model. I have many parts now compared to five years ago, but all of it is useless when someone knocks on the door to ask for a small scale model. This model also shows the problem of modern Technic sets from the store shelves. They are built large, very large. The 8265 Wheel loader is an example. It is enormous, while having less functions than this small crane that will fit into its bucket. Now the size may speak to the inner desire of the (hu)man to posess big things, but personally I like finesse and elegance over size. It is my big hope that TLG sees this in time, otherwise the awesomeness of new Lego Technic sets will fade away. The video

The video shows a rotating superstructure... not swiveling in a smooth way. I found this pulsating behaviour with an XL motor under a too heavy load. Of course, the superstructure is really heavy but in this model they have a high-quality turntable at their disposal!

In the side view, it seems that the crane chassis is bent and the superstructure seems to lean a little backbards. Also, it is striking that the pile driver boom contains almost no axles at all! Design to prevent color vomit? In the outtriggers, 5L LBG axles are used. So maybe Lego is listening in some way. The steering happens from the back. 8421 has a large 36t gear here to transmit steering force, while they choose a gear reduction and a smaller wheel for this crane (where the 36t gear was perfectly possible. This solution is less direct as gears have some play. Clearly, because of internal (space?) issues, the rotation direction of the axle is wrong requiring an extra gear combination at the output. The solution here is a 4L axle with stop supported by 2 half stud triangles. Yeah. Very sturdy design to push a >1kg crane forwards..

You are so saying what I think about this! The ranting goes on and on and on and on.. It becomes boring, really..