Can a mechanical clock be made on the Glowforge?

I tried this yesterday, but the pieces are too big or holes are too small, so I was not able to make the adjustments to the old clock.

It did run for a while after reassembly (before the frame shifted again and it eventually stopped).

4:15 PM came and went, and I still do not have a working :glowforge: :sob:

The UPS site still has that listed at the end of the delivery window, but no delivery yet…

It arrived! Late, but it arrived!

It is too late for me to play with it to much. I still have to get the kids cleaned up and help my son with a project due Monday… But, it is here. I am happy. :smiley:

It is SO pretty; it really is shame what I know I am going to do to it…


Well… I couldn’t wait. So I stayed up after the kids were put to bed to play with my new baby. But, I was a little concerned after I did.

Previously, these were the settings I was using to cut this new acrylic:

That will not cut through this acrylic on this refurbished machine. I had to lower the speed and bring the power back up to cut through it:

  • Speed: 115
  • Power: 95

I don’t know if my previous machine was just that much more power, or what?

Now I just have to do all the testing again to hone in these settings for this machine.

I have noticed that the angle of the kerf is different on this machine too. It is wider at the top, making the bottom edge sharper. But, maybe that is because I have time settings just barely cutting through to reduce the flash-back?

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I’ve been really busy lately, but I am still trying to make steady progress on the clock since getting my :glowforge: back and running.

This green-glass acrylic is simply amazing. I think this going to make a really nice looking clock.

(Again, I do not think the picture does it justice.)

I still need to finish the minute-axle, the hour-gear-down, the pendulum, and the face.

I am thinking about make the pendulum, hands, and face out of wood. The pendulum needs the friction to be adjustable. The hands and face being opaque would just make them easier to read.

I would really like to adjust this to run on a spring and make it a mantle clock!


All of those gears look really impressive.


It would be easy enough to make a slip gear that would allow sliding one click at a time, hold well enough in use but a slightly stronger pull bump the “clicker” into however many clicks above or below, Kind of like an escape gear but to escape in either direction



It might be easy enough to twist a rubber band like in those toy planes?

I had considered this, but it cannot provide the accuracy needed with the pendulum. This would require the placement to be at set intervals, but moving the pendulum weight a fraction of a millimeter would require the teeth to miniscule to the point that I don’t think would be possible with acrylic.

I had thought about this, but I don’t think it would run long enough. I want to run for at least a day between winding (more like two, if possible). And the rubber band would only allow an hour or two and would get worn out pretty quick (by my estimation).

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If the rubber band was through a wheel spun say 50 times a 4" wheel would provide 50’ of travel and could be wound very quickly. My old grandfather clock did only 4 feet of travel.

If you needed a timing belt there is this


I have played around with rubber band powered toys. I might play around with that if my required torque is low enough with the acrylic clock. A rubber band would definitely not produce as much torque as a two pound weight…


There is the time tested spring coil that provides consistent torque within the mechanical limits of the spring.


:thinking: I see what you did there :smirk:


What would be the great challenge would be building this in the sea glass acrylic :thinking:

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Now that I have all this scrap acrylic, I have been wondering if there is a way to recycle/reform it. Apparently, with the right heat and pressure, it could be reformed. But I do not have the machines or expertise to pull that off.

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Pictures just don’t do this justice…

After hours of frustration and reprinting pieces, I finally go this clock together. I am amazed at the lack of friction compared to the wooden version. I knew it would have less friction, but this is incredible.

I am trying to simplify the assembly, but still keep the frame reliable. I doubt this will be the final version, because I already see room for improvements and the clock isn’t fully assembled yet.

What is still left:

  • Trimming the brass rods (And figure out how to hold them in the frame – currently just held with tape.)
  • New pendulum design (Which already needs to be adjusted, because I realized it was not balanced. At least I noticed before I cut it out.)
  • The weight (Currently a 2 lb. bottle of water… yeah, still no inspiration there… but something out of this acrylic would be really nice!)

The reduction in friction will likely allow for a smaller weight (or a pulley system to all for longer run time).

Improvements I would like to make still:

  • Adjust the frame a little more, remove old brace holes not needed with new design.
  • Adjust the clock to run on a mantle?!?
  • Add a crank/key and ratchet to wind the clock (the original design attempted this, but it failed and was scrapped to focus on the clock work.)
  • Add a pulley system to increase run time.

I think it would take a major metal shop. I had a wax injector made using a base for keeping tar hot, but it had many issues (It is so weird how one looks without eyebrows when you give them a hot wax job) :frowning:
I was particularly interested in how prime numbers were used to provide the number of teeth needed.

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Check out this video of recycling acrilyc plastic

How to recycle acrylic


I actually ran into that video in my search! That was when I realized I didn’t have the machinery or expertise needed…

But, I would love to be able to reform these scrap pieces into new sheets (even if they were just small sheets).


Glad to see you got a working machine again, and are still plugging away at this. Also glad to see the improvements when you switched to acrylic - but now that has me wondering about using acrylic “faces” for the gears, i.e. a wooden inlay with a fine acrylic perimeter. You might curse me for that idea later - feel free, go ahead! :rofl: In all seriousness, that’s actually part of my plan/question below.

So - I had a question that I thought you might be quite well qualified to answer - and if you already covered it, I apologize. I did skim back thru the earlier discussion and couldn’t see it.

I was watching Clickspring’s Byzantine sundial calendar videos and pondering the gear tooth profile used. The Antikythera mechanism teeth are simple sawtooth. Modern gears use very different profiles.

Finally, the question - have you experimented with different tooth profiles? I have cut a few types to play with on a test board, but I’ve never built a mechanism like you have. I am, however, working on a project (a rotary engine cutaway) that would benefit from a low friction gear arrangement. I need it to run on as little power as possible (hence also thinking of acrylic/wood composite gears as mentioned above.)

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I did early on, before I knew as much as I do now… I was originally using a more “saw tooth” profile, but switched to my current profile for a couple reasons. The first reason was purely cosmetic; I simply preferred the aesthetics this profile, but then I continued with it because I realized that it gave me a wider range variance with the distance between the gears.

This variance is still quite small, but it can be used to account for minor axle shifting.

I should probably look at different tooth profiles again, now that I know and have experienced so much more.

I actually have thought about this. But I deemed it more work for little benefit at this point. It is just easier for me to cut the entire gear out of the acrylic and have less waste.

Another suggestion I read, but I haven’t tried, was cut the gear out of wood and then coat the tooth edges with super-glue. This is supposed to give them that “acrylic-edge” benefit.


Cold metal casting?

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