28 November 2023

LEGO® part 4042: Curved Bar with Axle End and 1 x 1 Round Plate

Posted by Elspeth De Montes

Thomas Jenkins thought it was time to take a closer look at an interesting new element that has been appearing in more and more sets since its release earlier this year.

Bar Curved with Axle End and 1 x 1 Round Plate is a bended element we first noticed in two LEGO® Marvel sets earlier this year, but do you know which set it was originally designed for? Read on to find out more...

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The Curved Bar with Axle End and 1 x 1 Round Plate has a Design ID of 4042 and the Element ID for Transparent /Trans Clear is 6444527. Its official TLG name is 3.2 Shaft w/ Cross Axle.

Look at this thing! This Swiss Army knife of an element has a stud, axle, and bar connections. It wouldn’t look out of place among the submissions we received in last year’s Make a Wishbrick contest


We asked one of the people responsible for this element, Yoel Mazur, Design Master at LEGO how this part came to be:
When developing the Avengers Tower, we knew we wanted to be able to pose minifigures and small builds in different locations around the tower. We started with this older element, no. 49546.

This older element has a 1x2 plate with studs and tube-side [anti-studs], 3.2 shaft, and a round 1x1 plate with another 3.2 shaft continuing onwards. That’s a lot! 

We decided to create a similar element that introduces a curve. To avoid a left or right designs, we chose to create a symmetric element, and therefore needed a back-to-back stud."

- Design Master Yoel Mazur 

This new element also looks like it might be an evolution of the much smaller minifigure action posing accessories, particularly Bar, Angled with Stud on End (65578), which were introduced in the DC collectible minifigure line a few years ago. Those were first seen in Trans-Clear too. (For a refresher, check out Jonas Kramm’s article about element 65578).

Other elements we think it shares some DNA with are:  

  • Bar 1 x 12 with 1 x 2 Plate End with Hollow Studs (49546)
  • Bar, Angled with Stud on End (65578)  
  • 1 x 8 with Brick 1 x 2 Curved Top End (30359).

As mentioned, the element has a bended bar with an open stud towards one end. The hollow stud is double-sided; a super-useful connection point, functioning just like a Plate Special 1 x 1 with Clip Light (4081).

At the other end, the element terminates in a Technic axle which provides a firm connection when used to suspend minifigures, however from a MOCing perspective it seems like more of a hindrance than a help. Yoel explained the rationale, when the element was developed for Avengers Tower:
Instead of a 1x2 plate geometry we used a cross axle, which is symmetrical and allows builders to connect and disconnect the element from the build easily. This is also why the Tower has many cross holes."

I really like how they used the element to "throw" Thor's hammer in the set. The clever use of the axle attachment for Wing 5X7, W/ Cross Hole, NO. 1 in Trans Light Blue (6508017 | 2149) works well to express power!


In case you were wondering, the tip of the bar and the axle are at an angle of 112.5°, which is equivalent to Technic Axle and Pin Connector Angled #5 (32015). I do love it when the LEGO® System reveals itself like that! 
The small 3.2 shaft coming out of the double-sided stud is 1 module long and at 22.5 degrees. When I design new elements, I try to keep them on grid as much as possible. This is an advantage later on when the fans find new ways to build with them. 

Stacking and tablescraps

So, how about building with multiple 4042 bars? I consulted the New E. Brains Trust for some ideas. 

Given that the plate portion of the element has a stud on both sides, a little thinking is required to line up the elements in-System. An easy solution is to fit the bar tips into an element with hollow studs such as a modified brick with studs on side.

Another option is to slide rigid hose or a bar through the open studs, though a little care is required to equally space out each of the elements. Given its spacer in the middle, a 2-module bar helps to create the correctly sized gap, but will only join two.

Elspeth DeMontes also suggested using 1x1 "nipple" tiles (20482) to create 1-module spaces between the bars. She also used lots of 1x1 Tiles with Clip in her tablescrap. I think this would make a great roof. 

Here's another variant using plates with clip and cheese slopes.

Thomas Jenkins’ MOC using part 4042 

Elspeth and I have suggested some ideas for using the piece in a structural way, but how about building something that takes advantage of its aesthetics?  These elements were seriously good fun to play around with!

When I looked at the element, it immediately made me think of a jellyfish's tentacles glittering in the sea. For inspiration, I looked at Tom Loftus' undersea MOC that he built while looking at the parts in 76391 Hogwarts Icons. One of the things I liked most about that MOC was the colour palette he used to evoke an underwater world,  so I tried something similar here.

If you're buying the Curved Bar from LEGO Pick a Brick, please consider using our affiliate link: Element 6444527. We may earn a small commission.

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  1. Nice review! I don't really collect Super Heroes sets but was happy to get my first one of this piece in the Insect Collection set.

    The design is smart—the cross hole connection ensures that it can support a reasonable amount of weight without falling out of position.

    As a big fan of themes like Ninjago and Elves, I could also see this being used as part of a "skeleton" to hold foil or fabric dragon wings. If it ever appears in a solid color like black I could see it being great for something like streetlights as well.

  2. "a bended element" … the usual past participle of bend is "bent" … the word "bended" is archaic and is now normally only ever used in the phrase "on bended knees"

    1. Tim changed my 'bendy' to bended so I guess he is archaic!

    2. Us Aussies are like so 240 years ago!

    3. Eleventy Thousand years old...

  3. I wonder what the tightest radius a bar can curve around before attaching clips would become illegal. I'd assume the diameter of Small Technic Steering Wheel 2819 (3 studs) is pretty close to the minimum...

    1. Interestingly, we have a post coming up shortly that addresses this!

  4. This is a really cool part, too bad it vanished from PaB before I could get any (it landed on the 11th and vanished on the 28th)

    1. It’s still there, just sold out. Unfortunately I only got 2 when I did my order because I was only thinking of posing flying characters, like in the Hocus Pocus set. Bricklink prices are very similar to PAB prices for this part currently but there are not a lot of sellers with more than 1-2 listed, at least in my country.

    2. I’m hoping it restocks, it should. I just saw a few other pars restock.

  5. Thanks for this look at the element! It's also a distant cousin to the minifig fishing pole, I'd say. Arranged side by side as some of your tablescraps it reminds me of the modular cells in which Space Police used to imprison agents of Blacktron.

    Getting this element in other transparent colors would be fun, as would more common colors like black or grey for building architectural details and especially fences.

    Your pic with the older element 49546 really highlights the difference in transparency, a shame we couldn't keep the older plastic for this new part.

    1. They sure would make a cool Space Lockup! Just need them in red of course :)
      Yes it is sad MABS is less transparent. It's exciting that they can mould more part in it, though.

  6. Hmm I need to figure out how to post with a name here.

    Thanks for this highlight. I totally underestimated this part.

    I am totally shoe horning this in here, but you gotta. Check out Maxim Baybakov’s awesome ‘North Tower’ MOC and how he created the curve in his tower. Really gets the creative juices flowing learning techniques like that.

    Also btw your site has been my favourite Lego site so far.

    1. Thanks, I checked out his North Tower moc on Insta - pretty parts intensive but looks so good.