Back to the Basics -- Clock Escapements

I see there are lots of students and teachers on here… I’m just an old hacker with some new toys. While looking through all of the curriculum I noticed they do a very good job explaining gears, levers, etc., etc., however they do not hit on the very basics of motors. Instead they just have you plug in a motor and program it.

I thought I’d share something I was teaching my daughter, Clock Escapements. The essential brain and power of mechanical clocks. Simple yet complicated. Perhaps this could be something the students could leverage for understanding the basics of power generation and control.



I built another clock escapement… this one is much closer to the normal tic-tock vs the previous one which was more like a stopwatch.






Nice! I especially like the second one.

I’ve been away from the forum for a bit, and THIS is what you get up to?!? Okay, so I recently, (as in yesterday!) picked up a model kit for a da Vinci clock - see photo.

I’m teaching a summer physics course for middle schoolers and we’ll be looking at lots of different kinds of motion. The course is designed to introduce physics concepts, but we’ll also be doing a number of “minute to win it” type challenges using levers, inclined planes, pulley systems, etc. Should be fun :slight_smile:

I was thinking I might try a vex waterwheel clock or perhaps some vex version of the marble clock. Thanks for the motivation!


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Great minds thing alike! I took photos of several Da Vinci models while at Hobby Lobby, I have plans to duplicate them with Vex gear. For the clocks, learning how to make Vex conduct the escapement task was phase 1. My next revision will be more direct and stronger allowing the gears to turn more gears needed for the clock hands. Now, I just need more Time to play with Time machines.

I saw someone made a marble clock out of Lego’s on YouTube… if they can do it, you know you can do it! Love to see it done.

So I played around with this last night and created a simple escapement using a 40-tooth sprocket and tank tread for the crown gear. I placed 1x connector pins at various intervals (ultimately 5 at 8-tooth intervals) and then used an axle and 30 degree angle beams to create the verge and pallets…

Seemed to work smoothly, so I moved on tonight to gearing. So far, I think my best configuration is an axle with a worm gear for the second hand. Using the worm gear to drive a standard 60-tooth gear achieves the 60:1 ratio for the minute hand.

This then drives a 12 to 36 (3:1) coupled with a secondary 12 to 48 (4:1) - result is the 12:1 necessary for the hour hand. Still working the kinks out, but hoping others will try something similar and add to the discussion. I’d love to see a gallery of clocks, as there are so many possible designs!

Good luck (of the Irish) to all! Happy St. Patrick’s Day :wink:

Added: link to a short video of my basic escapement mechanism.

FYI: I’ve been having issues with my mobile since updating it this morning, so please post back if you can’t view this video.

Very cool… and you figured out the gear ratios. I’m very interested to see this project. I need to step on the gas with mine to finish before I pack everything to move to a new home.

Over the weekend I put together another clock escapement, i’m happy with the nice tic-tock sound and pendulum action. I included the seconds, minutes and hour hands/face-plates… however I did not work out the gear ratios at all causing the seconds to lose 8/min and the min/hour are way off. No excuse other than laziness. :slight_smile:

Reading your post on the ratios helped, i’m hoping to have them all corrected by next weekend (time permitting).


There’s a lot to be happy about in your build. I think it turned out great! I really like the pendulum, too.

A few hints you may already know…
Pendulum length will effect the timing. So, even after the ratios are in order, you’ll still have to adjust the run time. Pendulum length and weight are both factors. Longer pendulum / less weight = slower clock. Shorter pendulum / more weight = faster clock.

My vision for mine is a bit different, but like you, I have a few other things on the burner this week. Best of luck with the new house, by the way :slight_smile:

Still, I’ll definitely be posting something when it’s done. I have the gearing and the escapement components both built; I just need to merge them into one efficient clock…

Thanks for getting this idea going. Hope others give it a try.

Yep, I’ve spent a lot of time reading DIY clock sites… its a pretty cool area of expertise and the creativity is endless.

My escapement wheel takes 2.88 seconds for 1 rotation. If I can get it to 3 secs, I should be able to get the gear ratios worked out. Ideally, 4 secs for 1 rotation would be the best. I’ll need to nearly double the pendulum length.

For the seconds hand, are you gearing off of the escapement shaft or the weight shaft? This is where i’m getting confused, the DIY sites seem to swing both ways on that.

For your weight, are you using Vex pieces or a bottle of measured water for precise oz’s?

I’ll try to explain this without photos - volunteering with vex today, but my toys are at home…

My second hand is on the same shaft as the 60 tooth being driven by the worm gear. The worm gear is driven by the escapement. Current thoughts are to couple these so that the weighted drive wheel (gear ratio to be determined) drives the worm gear.

With me so far? The weighted drive mechanism will also use a pulley at the bottom of a loop of string that rises back up and anchors to the clock. By using two strings, I’ll achieve twice the travel distance for the same height off the floor (most grandfather clocks use this method).

Now for the wild idea I had this morning. Ready?

Could I use an overbalanced chain or other “perpetual motion” device as the weighted system? Probably not. But I am thinking about possible ways to lengthen the run time between windings. Mostly mental gymnastics, but a fun use of all those unused compute cycles throughout the day :slight_smile:

Weight: so far it’s just a container of BBs / steel marbles while I experiment. Once I have the final clock built and the weight adjusted, I’ll switch to vex parts. I think I have enough wheels to achieve anything I would need!

Interesting, I didn’t think about using a worm gear. Going to need to dig those out and play with them.

In the second escapement I built, I used compound gearing and it will run for about 40mins. The current clock, when I compound gears I have to add so much weight it starts to tip and stress the structure. I get about 10mins out of it. The math game in this clock challenge is something else… lol…

I’d like to know more about the two strings, good idea and seems like it can buy lots of time. For winding, did you come up with a way to wind the string where the escapement doesn’t stop? I was leaning towards some kind of ratcheting system, similar the one on catapults. Haven’t had much time to play with time lately, Been drowning in my job the past 2 weeks.

I know what you mean about the math. Also, trying to create - rather than just copy - makes it even more challenging. Current version only runs about 10 minutes (not real time - clock time). Still no method for winding, either. I’ll think more about that, too.

Here’s a couple quick shots of build 2. Still trying to keep the workings compact, yet open and visible. Wish I had more time lately, as well. Builds don’t usually get interesting until about build number 7, and only on number 2 - lol

On vacation with my wife this week, so not much will get done on the clock. However, I’ll try to post a video of the current movement. Note: I must admit this needs LOTS of adjustment for this version, but it’s still kind of fun to watch!




Here’s a link to a video of this clock’s movement:

WOW… WOW x 10! … that is really nice!! The detailing and setup is very well thought out, you raised the bar pretty high. :slight_smile: You should submit that in the Vex Inventors Portal.

I watched the video about 40 times… lol… i am really impressed. wow…

Thanks. Looking forward to build #3 myself :wink:

I got my next clock infrastructure built enough to be stable. I spent a lot of time on the pendulum length/weight and escapement system and got one of the drive gears between the escapement shaft and weight shaft to rotate 3 times per minute. Once I can validate all of the hands gearing works, i’ll get it stuffed into the framing… just hope the cosmetics can remain in tact.

This is the gearing I can up with for the Seconds, Minutes and Hour hands being driven from the drive gear shaft:

Drive gear for escapement shaft rotates 3 times per minute which will drive the seconds gearing and so forth…
Seconds Hand Gearing: 12:36 or 36/12=3 for a 3 to 1 rotation
Minutes Hand Gearing: (Compound) 12:60 --> 12:48 --> 12:36 or (60/12)(48/12)(36/12)=60 for a 60 to 1 rotation
Hour Hand Gearing : (Compound) 12:36 --> 12:48 --> 24:12 or (36/12)(48/12)(24/12)=24 for a 24 to 1 rotation

Does that look correct?


Sorry for the delay. Phone issues persist. Logged in earlier to see if my settings were off. Whatever the cause, now I’m not getting emails from the forum :frowning:

Wow, 3 rpms! Awesome! How much weight are you using???

Number ratios look correct. Not 100% sure as it’s so easy to reverse the ratio by putting the driven gear first instead of the driver gear - speed vs. torque - depends on your perspective, I guess, but I trust you are correct.

I am curious how many actual gears this setup takes. For example, are your minute / hour hands running off the same 36-tooth gear powering the second hand, or are you using multiple drive trains? Does this added gearing increase the necessary torque and thus slow the rate of your escapement?

Maybe you could post a photo of the gearing (an incomplete build is fine) taken from the side?

If interested, my build #2 is actually quite easy to divide, so I can post images of just the second/minute/hour hand gearing. Likewise, when I separate it, the gearing of the escapement remains intact. (BTW: My escapement rotates at 12 rpms, 5 clicks per roatation.)

Let me know if I should bother with photos before disassembling, else I’ll probably just start over when I start build #3

Also, not sure if you’very tried a worm gear, yet, but my minute hand is, as stated in an earlier post, running off a 60-tooth powered by a worm gear. 60:1 ratio with only two gears :slight_smile:

Finally, I might be out of touch this week, but keep posting; I can’t be the only one reading these - LOL!


You hit on some good points that i’m starting to deal with as I start to assemble the gears in my frame, i.e. adding more gears slows the system down a bit. I also need to deal with shafts spinning the clock hands backwards, need some fancy gearing to get them right… fun stuff!

Below are some photos of the front and back, its just slapped together for proof of concept. The gear with the white pin is the gear that spins 3 rpms and the weight is 4 medium wheels and 2 large wheels. The gears for the hands I had quickly put together on a long 2 x 20 so I could spin them and validate rotations, they’re taken apart now. Anyways, once I get all of the gears into place i’ll need to make some adjustments to the weight and/or pendulum of course but it should be minimal.

Here’s a video of the pendulum… its my favorite out of the 4 I’ve crafted.

You don’t need to pull you’re clock apart, I learned a lot just from the video. :slight_smile:



Sweet pendulum! Thanks for posting it. I’ve been checking back daily in hopes of another post.

Sadly, I won’t have time to build for a while, but I might just have to try a pendulum on my next build!

General invitation: If anyone else IS reading these posts, please join the discussion. I’d love to see and hear what others can add to the thread :slight_smile: