Time bridge - a steampunk clock

[Davidz90]

Here's a project I have been busy with for the past few months:

In general, the goal was to create a contrast between orderly, architectural base and somewhat chaotic, steampunk-styled mechanism on top.

Here's a better look at the mechanism:

It consists of three major modules: Main dial with time and calendar in the front, the actual clock mechanism in the center and striking mechanism in the back.

The front dial looks like this:

The two bottom dials are day and month. Behind month pointer, there's an encoding wheel that encodes the length of particular months. The day dial has 32 divisions and at the end of the month, the hand jumps from 28,30 or 31 to 1.

And here's the striking mechanism:

The key part is the spiral-shaped "crown wheel" that encodes numbers 1-12. Gear rack (behind propeller piece) is allowed to fall on the crown wheel. Then, the mechanism lifts it 1 toth at a time, striking the bell. The number of strikes will depend on how far the rack has fallen, which depends on the crown's position. This is a varian of a more common "rack and snail" mechanism; the snail cam was very problematic to make wih Lego, hence I came up with the crown idea.

Here's the base under construction:

The internal Technic reinforcements are sturdy enough to use the arches of the bridge as handles, so that the whole thing can be moved with ease. There's also enough internal space to install lighting:

 

A video of the clock is here:

 

 

 

[allanp]

Lovey mix of art and engineering, very impressive.

[Davidz90]

5 hours ago, allanp said:

Lovey mix of art and engineering, very impressive.

Thank you! In terms of engineering, one of the novelties in this clock is so-called gridiron pendulum. It uses an array of rods made of different thermal expansion materials so that the whole thing doesn't expand. Normally, they are made out of brass and iron. Here, I used Lego (ABS plastic) and steel. It looks like this:

and to build it, I had to measure the exact thermal expansion coefficient of the bricks (ABS plastic has a wide range). Results were as follows:

Steel is missing from this table, but it similar to copper; Lego expands about 4 times as much as steel. Interestingly, liftarms and axles are made out of different plastic and they have quite a different expansion coefficient. This can be used to make pure-Lego gridiron pendulum or some other contraptions where something moves with temperature (thermometer?). 

 

[jorgeopesi]

I do not have any idea about clocks but that is a lot of an awesome work, congratulations.

[Jurss]

Really impressive, it is not only clock with technical features, but also really piece of art,

[Davidz90]

13 hours ago, jorgeopesi said:

I do not have any idea about clocks but that is a lot of an awesome work, congratulations.

Thanks! Yeah, it is a rather niche topic.

4 hours ago, Jurss said:

Really impressive, it is not only clock with technical features, but also really piece of art,

Thanks! Indeed, that was a goal here; in the past I had a few ornamental clocks and a few complicated ones, but never both.

By the way, I forgot to mention that thanks to the temperature-compensated pendulum, the clock keeps time to within +-2 seconds per day; it is one of the most accurate ones I have built.

[1963maniac]

That's beautiful and an incredible work of engineering to make a clock work from Lego toys!!!!

[Francois Y]

C'est très bien réalisé, bravo !

[Davidz90]

On 4/12/2026 at 2:59 PM, 1963maniac said:

That's beautiful and an incredible work of engineering to make a clock work from Lego toys!!!!

Thanks! There are quite a few enthusiasts who are building working clocks with Lego, some of them got me into this hobby ~10 years ago. Just searching "Lego clock" on Youtube leads to a deep rabbit hole :) Thanks, in part, to my efforts, the art of Lego clocks reached the stage where they surpass regular low-end grandfather clocks in terms of accuracy. 

17 hours ago, Francois Y said:

C'est très bien réalisé, bravo !

Merci :)

[1980SomethingSpaceGuy]

A true work of art! Brilliant!

[grum64]

Absolutely Astonishing. I can’t think of anything else to say that would  do it justice.

[LEGO Train 12 Volts]

Clear functions but mechanism too complex for me, a true work of mechanical engineering and artistic masterpiece!

[Davidz90]

3 hours ago, 1980SomethingSpaceGuy said:

A true work of art! Brilliant!

Thanks!

3 hours ago, grum64 said:

Absolutely Astonishing. I can’t think of anything else to say that would  do it justice.

Thank you! This clock is designed as a showpiece first, timekeeper second and it seems I succeeded in that.

1 hour ago, LEGO Train 12 Volts said:

Clear functions but mechanism too complex for me, a true work of mechanical engineering and artistic masterpiece!

Funny thing, I can't quite wrap my head around some of the gearboxes posted here, but this feels simple to me :) The calendar was the most problematic part; why every month has to have a different length, with no pattern to it...

[Kalais]

This is crazy! (in a good way :) )

[Joostv]

On 4/12/2026 at 5:07 AM, Davidz90 said:

Thank you! In terms of engineering, one of the novelties in this clock is so-called gridiron pendulum. It uses an array of rods made of different thermal expansion materials so that the whole thing doesn't expand. Normally, they are made out of brass and iron. Here, I used Lego (ABS plastic) and steel. It looks like this:

and to build it, I had to measure the exact thermal expansion coefficient of the bricks (ABS plastic has a wide range). Results were as follows:

Steel is missing from this table, but it similar to copper; Lego expands about 4 times as much as steel. Interestingly, liftarms and axles are made out of different plastic and they have quite a different expansion coefficient. This can be used to make pure-Lego gridiron pendulum or some other contraptions where something moves with temperature (thermometer?). 

 

This build is absolutely awesome and I love it 😊.

An application of the different expansion coefficient that comes to mind is a Gerrit van Bakel style walking machine. That artist has made a couple of moving sculptures that move (extremely slowly, like millimeters per day) based on changes in humidity or temperature. https://www.gerritvanbakel.org/ 

[Davidz90]

3 hours ago, Joostv said:

An application of the different expansion coefficient that comes to mind is a Gerrit van Bakel style walking machine. That artist has made a couple of moving sculptures that move (extremely slowly, like millimeters per day) based on changes in humidity or temperature. https://www.gerritvanbakel.org/ 

Thanks for the link! Very interesting, didn't know about this one.

I considered building a clock powered by changes of temperature or pressure (like Atmos clocks), but Lego escapements are far too inefficient for that. However, wind powered clock is something I'm planning to do.

By the way, your Tic-Tac-Toe machine is a work of art!

[Joostv]

9 hours ago, Davidz90 said:

Thanks for the link! Very interesting, didn't know about this one.

I considered building a clock powered by changes of temperature or pressure (like Atmos clocks), but Lego escapements are far too inefficient for that. However, wind powered clock is something I'm planning to do.

By the way, your Tic-Tac-Toe machine is a work of art!

A wind powered clock would be awesome, hope you will post that here as well.

And thanks 😊

[Elysiumfountain]

That is stunning! I love the transition between the mechanics on top to the stone based architecture to the natural base. Great job on this, it's so mesmerizing! 

[Davidz90]

3 hours ago, Elysiumfountain said:

That is stunning! I love the transition between the mechanics on top to the stone based architecture to the natural base. Great job on this, it's so mesmerizing! 

Thank you!