Can a mechanical clock be made on the Glowforge?

Here is a “clock model” I made based on the designs from stephenjressler.com:


I call it a “model” because it is not a working clock. It is not even glued. I see several changes I want to make before I try to make a working clock.

I learned a lot just piecing this one together, and I would really like to try to use printed axles. I just hope I don’t make things more difficult for myself by eventually doing that… It will require my clock to be larger I think, but that will be fine.

While reading, I learned about a “springed pawl and ratchet” configuration for a one-way gear that looks amazing! I was trying to use a gravity-pawl-and-ratchet system that might still work, but there is elegance with the spring that I really want to try.

A spring-and-weight pendulum system is really intriguing also. I think that could be fun, but a normal pendulum seems like the best place for me to start with.

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That’s the way to do it… experiment, not expect the first finished piece to be perfect!

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That is a really clever clock face design. If I am seeing that correctly, the input to the clock face is geared up for the minutes, and down for the hour?

I bet you could power that from the same type of motor you were trying to use on your marble run.

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The minute hand is directly attached to the power-drive. Then the hour hand is attached to a gear that is geared down from the minute hand.

I would prefer the minute hand not directly attached to the power axle, so it could go longer without needing to be rewound. But, I don’t have much experience with this yet. So, I am just following different examples and looking at different clock designs.

Yes @eflyguy , I cut the main escapement gear, the pendulum and one of the minor gears, all from 1/4" clear acrylic. (Actually I repurposed an large office rug protector sheet which is all scratched from years of chair bearings rolling on it, so I turned it into “frosted” acrylic by passing a 800 grit sander).

The largest acrylic parts did indeed warp a little, enough to be noticeable when revolving around an axle, but I corrected the distortion with careful application of a heat gun and a some patience. However unlike the MDF conterparts, after being straightened, the acrylic gears have remained true and unaffected by ambient heat and humidity.
I have yet to experiment with plywood gears.

Also all shafts are polished brass and tubes, with bearings only for the pendulum.

Here is a short video of the hybrid MDF/Acrylic design.

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I think this will be key when I try to make a working clock.

I think it will be fun to make one that can be completely cut from the :glowforge:, but I think that is less practical. And it would not hold up to wear-and-tear as well as a brass rod would.

I look forward to learning and experiencing so much more with clocks. This is such a fun space to work in! I think a clockwork structure that just continually moves will be fun even if it doesn’t keep time. (That is actually where most of the fun is, because you don’t have to worry about the timings and keeping them!)

Edit: @reynoso I just saw the video you added! That is so awesome looking! I still don’t see what keeps the pendulum from slowing down, unless it really is the power-source… I have so much to learn…

From my post above

The reason I chose this plan over others with a real 0.993 m pendulum (which is what you need for an oscillation period of 2 seconds) powered either by a conterweight or a spring, is that it uses a short 0.33 m pendulum assisted by a simple 1 transistor battery powered electromagnet coil circuit to push a magnet on the pendulum ever so slightly to counter the inertia lost to friction. However the circuit does not control the accuracy or timing of the clock, but rather a weight adjusted up or down at the bottom of the pendulum to adjust the period of the oscillation.

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Wow, that is awesome! So I wasn’t crazy when I thought the pendulum as the power-source. I will have to look more closely at that Magica Wooden Clock! That looks like a really amazing power source with the electromagnet.

Well if you think about it, somewhere in your gearbox there will be an axle that is turning at 1 rotation per hour, and that is your minute hand. The distinction is all in your mind: Where does the gear drive end and the clock face start?

You can increase the runtime of your clock by adding more gearing to your gearbox, limited only by friction. Of course, the pendulum period has to be adjusted accordingly.

That is a very interesting escapement.

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I went ahead and glued the wheels and pinions together to allow them to spin freely on the axles. I attached the face-plate (with some spare parts I had lying around) and cut out some frame braces to hold everything together.

I am really surprised at how well it all works together! I do not have a weight to drive it or a pendulum to regulate it yet, but the gears all work as expected. It has made for pretty cool clock model.

The escapement prevents me from spinning the gears forward (as expected), but it will let me spin them backwards rather easily.

I ordered some brass rods for when I try to make the real thing. I will use those for axles instead of the dowel rods and bamboo skewers I am using now.

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A video would be cool… :thinking:

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It sure would be cool! Everyone loves a video of :glowforge: goodness put into motion!

It took me a bit because I wanted to replace the spare parts with :glowforge: printed spacers (and apparently videos are very limited here, I had to edit the video four times to get it to work!)

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Is that all draftboard?

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Yes, the model is made entirely of draftboard. I had a few nuts and bolts holding stuff together at one point, but I replace them with custom spacers and press-fit tabs.

The whole thing works WAY better than I ever expected. The hour gears stick a little too tight to the drive shaft, causing the minute hand jerk when it builds up enough torque to free itself. Other than that, if I put a pulley and pendulum on it, I think it would work (but I don’t think it would keep time.)

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… but will it turn in the correct direction? :rofl:

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If I turn the gears forward they get caught on the escapement and will be regulated by the pendulum. I did not expect it to be able to turn backwards so easily, that was just a happy accident for me :slight_smile:

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Right now the design (minus the pendulum and weight mechanism) all fit on a single :proofgrade: medium Draftboard.

I was going to try to make it larger for when I really try to make a working clock, but this size might work. I just need to make a few adjustments and make sure I adjust for kerf with the sizing.

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Are you going to stick with draftboard, or try acrylic?

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That is a good question… I don’t know yet. I definitely want to experiment with acrylic too. The warping kind of scares me a bit, but it sounds like the draftboard will have that issue to, over time.

I have been looking at playing with some Delrin. I think if I want smaller gears that is probably the direction to go?

Thicker acrylic may be fine. I’ve never worked with it but it was reported above to be less prone to warping.

I’ve not cut delryn on the GF. It looks promising - but I think clear 1/4" acrylic would look amazing.

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