Plywood would work, but the solid would would be more aesthetically pleasing. I got some solid cherry and basswood with my Glowforge.
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In my experience, you’ll be (a) hard pressed to get straight/flat hardwood large enough and (b) when you cut from it, it’ll likely release internal stresses and twist - especially over time (often not very long.)
I have a number of strips (not sheets) that I have selected from the stash available at a couple of local Rockler stores. Even cutting “modest” sized parts, they don’t hold their “flatness” like ply. I’ve made puzzles from mixed hardwoods and the pieces often don’t lay flat after cutting. There’s good reason you don’t get 12x20 sheets of decent hardwood, but veneer, that can be laminated (i.e. plywood), is commonplace. It’s also why most cabinetry is ply.
Anything that is made from hardwood usually has much thicker components than we cut on our machines.
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There are species that would work but they would be very pricy. It would have to be extremely hard and dimensionally stable. Wenge is commonly available and might hold up. Lignum Vitae was used traditionally but extremely rare now (partly for that reason)
The Wood Database has lots of info…
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The pendulum is thin, so strength is definitely a requirement.
I may need to adjust the design so I can use smoother material (like acrylic). Maybe use a nut and bolt for greater tension?
As a side note, I just checked the clock this morning (running fine for several days now) and it appears to be on time too. I will keep monitoring it, but it appears I have dialed it in, just in time to change up the pendulum… At least I know it is working perfectly.
Maybe I will wait to mess with pendulum again and go ahead and design I nice weight holder?
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It is so nice to have the clocking running so well, I almost don’t want to touch it. I am afraid I would mess something up and it would stop again.
I added more weight to old draftboard version and it started running for a short time again. I think with the improvements I have made I could probably get the wooden version to work also, but I just love the green-glass acrylic to much.
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New rabbit hole… my friend just sent me this:
/https://files.cults3d.com/uploaders/14024600/illustration-file/97a52962-4fb6-4b7f-bf53-dd8fd4d18575/loop.gif)
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it would be a terrible thing if you developed and shared a laser-able version of this. I would really hate it. I would never forgive you. never. ever.
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I would love to make a mechanical-digital clock. But, I would have to work out the segment first. Which I would likely share if I figured it out… I just need time right now, and with the summer it seems like I don’t have enough of it.
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This was already included in my design above, but I finally implemented it on my clock.
The counter-pull string for winding clock.
And wow! I should have done this immediately after implementing the ratchet, it makes winding the clock a breeze. It wasn’t hard before, but now it is also super fast to wind it.
I added a second drum for the cords to wind/unwind separately. I also had to move the small spacer from the back to in front of the decorative gear on the top (otherwise, the decoration could rub on the second drum).
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I think I fell in… stupid rabbit hole.
I will probably start a separate thread for this if I get much deeper.
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Thinking Jacquard Loom or player piano?
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I am really busy and will be away most of this week, but I was referencing the rabbit hole my friend sent me.
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The clock has been running really well. I have been winding it each morning, so I am guessing (based on its location on the wall) it can run for about 28-30 hours.
I looking at adding a pulley system to the weight. This should double the runtime, but I will likely need to tweak the pendulum again since it will also reduce the torque generated (unless I adjust the mass as well).
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Well, a small concern has come up with the clock… after 17 days of running perfectly, the drive-gear appears to have come loose and disengaged the minute-gear. This caused the drum and entire drive-axle to spin freely with the power of the weight. The weight bounced off the floor with a loud thud. All of this happened around 3 AM in the morning…
The counter-weight was shot up so quickly that it was tangled with the pendulum (that is the cord in front of the clock face).
I was able to untangle the cords and re-align the drive-gear. The clock is running again, but now I am considering gluing the drive-gear in place. I currently have not use any glue in the clock, but I am thinking it might be needed to prevent unnecessary shifting.
I am just glad the clock (or anything else) wasn’t damaged by the violent release of energy the was unleashed in an uncontrolled manner.
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After 23 days (and only one other incident) the clock stopped running this morning.
Upon further examination I found that axle that holds the weight-drum had slipped out of place. It pushed through the duct-tape that was holding it. I guess it is time to actually glue the caps in place.
The clock is probably due for a good cleaning also. I love the aesthetics of having the gears out, but I understand why the old mechanical clocks were completely enclosed.
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Awesome! For awhile it was looking grim for that kind of duration. Perseverance 
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Yep, and both issues could have been prevented if I just would have used glue.
I am trying to determine what the best glue to use would be? Since this is clear acrylic, I don’t want it to fog if I can prevent it.
I am thinking about trying Goop, since I already have some of that and have used it for acrylic before (just never for clear acrylic).
Goop might be okay - not sure of the tensile strength in this application. The other one I was thinking was E6000. Seems you’d only need a drop or two.
Very careful solvent welding would also work but you’ll never get it apart again and you have to be super careful not to over apply and get that spillover fogging.
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For acrylic, just the smallest drop of acetone should weld two pieces together. Just be sure not to apply too much.
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I like the idea of welding the two pieces together, but will it still be crystal clear, or will it cloud? That is my biggest concern since this is clear acrylic.
I will definitely be running some tests before any glue touches my clock.