Wooden Gear Clock and Stand

[iSawitFirst]

I'm building a wooden gear clock designed by Clayton Boyer. I'll mount it on a stand that I've designed and need some build suggestions for the stand. . The clock dial and wheels will be Birch plywood, the stand Sapele. The clock frame (the airplane looking thingy) will be Sapele as well.

My plan right now is to extend the top piece, a 1" x 1" x 7' piece all the way through the stand to the base and build up MDF and Sapele around it. This will lock the various "steps" around a reference point and tie the stand together from top to bottom. My concern is that the 1' x 1' piece probably won't be straight for the full length and could throw the pieces out of plumb. I won't have any ability to anchor each segment to the other due to the depth of each segment (can't put a base in each segment and nail it to the top of the lower segment).

Can anyone give me some options for tying the vertical segments together?

Thanks much.

Phil

[Lawrence Brown]

For such a tall, thin piece, you might want to investigate going with an armature: basically a piece of square metal tubing that runs through the middle. Otherwise I think you're right in worrying about warpage. Probably wouldn't be the most stable, and that pendulum is going to be quite finicky about it's positioning. Off a few degrees in any direction may make it stop.

Another thought I just had would be laminations (plywood) for the stand with veneering or a thinner finish wood around the outside. That would make it a little denser and more stable. I'd also fill the base with lead shot or something. You may have problems with vibrations if it's too light.

And a third thought would be some kind of tensioning with thin metal cables, like the rigging that keeps a sailboat mast rigid. It would change your design a bit, but I think it would still fit if done with the right type of cable and fancy connectors.

I hope you get it figured out though because it's a sweet looking design.

[iSawitFirst]

Thanks, Mech. I'll going to use a steel tube for all but the top-most portion that will be wood. I've already planned for lead in the base.

The base will have leveling feet so slight variations in plumb and dimensions can be adjusted out to keep the clock level.

I've done detailed drawings for each segment and this is really going to test my skills (YES!). Each segment will have splined miters. I'm also going to use maple for the top of each segment, again with splined miters.

I'd better put a fresh battery in my Wixey digital angle meter.

[Lawrence Brown]

You might want to put a secondary leveling mechanism right where the movement itself attaches to the base. Then you can use the adjustments at the bottom to get the base spire looking right and fine tune the movement at the top. Wooden clock movements are fairly sloppy by necessity because of the wood expansion and whatnot, so a tiny bit off shouldn't cause that much of a problem. There may also be an independant adjustment of the pendulum right at the escapement (most grandfather clocks and other "tall clocks" have this), so it will in effect be self-leveling (the pendulum will be self-centering), but it doesn't hurt to be able to adjust things.

I'm still a little concerned with the length and thin-ness of the base amplifying vibrations up to the clock, but hopefully you'll get enough mass inside it to dampen some of that. I'd even fill that steel tube with lead shot to give it more mass, but that will only help if you can also put enough in the bottom to keep the center of gravity near the bottom. Otherwise you'd just make it more unstable again. without enough mass, the pendulum itself can set the base to vibrating, which could cause the clock to stop since it can suck energy out of the pendulum.

Beyond the clock itself, you will of course want to find the most stable location possible, away from things like people walking and so on. It really wouldn't be overkill to put a slab of granite or marble underneath it to at least partially decouple it from surrounding vibrations.

Vibration is going to be your worst enemy with this one. A fun fact: if you put two pendulum clocks on the same wall, the vibrations from one will influence the other one, causing it to slow down, speed up, or possibly even stop. The vibrations basically take energy from one and give it to the other. Usually they will oscillate back and forth. Most of the time people don't even notice because it can take days or weeks to see a difference, but it's measurable.

Anyway, I really hope you succeed with this one because it's such a cool design.

[Derekkest]

Isawit, that looks like a fun one. I just received my ""Galileo's Bicycle Kinetic Sculpture" plans. My father saw it and wants me to make it for him.

I am really thinking about trying one of his clocks though, I have always liked the swoopey one

[iSawitFirst]

Mech,

Thanks for the tips. I decided last night to see if I can find an aluminum tube rather than steel. The steel will add weight to the top and I agree, it may be somewhat unstable. Putting lead shot in the tube is a great idea. I'm also considering hollowing out the base plate and putting lead in that as well.

A second adjustment is probably a good idea. I'll look at designing the clock frame-to-stand so I have the ability to adjust pitch and yaw.

Derekest,

Yea, Boyer has some great designs. I have plans for Solaris and want to build Nautilus as well (I think using a wind chime for the gong is way ) .

But, I've got to survive this one first.

[iSawitFirst]

Oh, and I made another decision last night. Trying to align and spline miters on all the corners will take way longer than I have so I'll use rabbits and dadoes. The vertical grooves won't be positioned directly under the above segment's corners but I can live with that.

I've also decided not to use Maple on the top plates of each segment. I think it would make the overall composition too busy and would distract from the Birch clock gears.

Maybe a Maple pendulum face. Hmmmmmmm.

[Lawrence Brown]

I don't know if you want to go this route, but this would be the perfect project for veneer. A lot of the clock cases used to be made this way and they looked great. Then you wouldn't have to worry so much about joints and so on. It would also let you get just the perfect grain all going in the perfect directions without too much fuss.

And anothe thought: (can you tell I work with clocks?) You probably are already planning this, but once you have the clock itself done, mount it temporarily to the wall and let it run for a while just to be sure that everything is working properly. You wouldn't want to get the stand all done and then be fighting with it and it turns out to be the clock itself.

Oh, and are you going to make the style of the pendulum mirror that of the base? don't know if you are making a custom one or what, but that would really tie the whole thing together.

Dang it, now I want to go cut gears!

[iSawitFirst]

Excellent point about wall mounting the clock first. I'll do that.

I'm still thinking about the design of the pendulum. The plans call for a simple disk (which I've drawn) but to me, the pendulum is such an important design element that it warrants something special. Because it swings in an arc I feel that it needs to be a round form of some description. The disk mirrors the face and all the gears so I'll probably keep that shape. Maybe I'll do some inlay in it.

I've become worried about the small size of the base (12" x 12") and will look at designs for making it larger. While I really like the tall slender form, reality rules and you're right, the stand must be vibration free.

[PaulMarcel]

For the pendulum disc, there's another thread on here for turned pendants. Turning the disc like that out of some stellar blank would be nice. The guy explained how he did it in the thread.

[iSawitFirst]

For the pendulum disc, there's another thread on here for turned pendants. Turning the disc like that out of some stellar blank would be nice. The guy explained how he did it in the thread.

Thanks for the idea. I'll do a search.

[iSawitFirst]

Found it. The pendulum has to be filled with BB's so I'll have to figure out how that can happen with a turned piece.

Don't want to eject a thousand BB's at 2500 rpm.

[Lawrence Brown]

Depending on what color you want the pendulum bob to be, you should be able to get by using a heavier wood and no BB's. If you know what the weight needs to be at what distance, then you may be able to just make the pendulum bob a bit bigger around to give it enough mass.

On the other hand, just like mounting it on the wall first to be sure it works, you may want to make the pendulum exactly as described in the instructions just to be sure of how it works before customizing. They can be tricky because what you are trying to do is get the center of momentum, which is similar but not exactly like the center of gravity, to be a certain distance from where it's hinged. If you just used a straight rod with no bob, the center of momentum would be at the exact center of the rod. Adding that mass to the bottom shifts it down. Once you get the center of momentum to be about the center of the bob, making the bob heavier doesn't change the speed of the pendulum, it only makes it swing out further. This can actually make things worse if the increased swing distance makes the pins push past the extents of the escapement.

Does your head hurt yet?

[Onboard]

Found it. The pendulum has to be filled with BB's so I'll have to figure out how that can happen with a turned piece.

Don't want to eject a thousand BB's at 2500 rpm.

Depending on what color you want the pendulum bob to be, you should be able to get by using a heavier wood and no BB's. If you know what the weight needs to be at what distance, then you may be able to just make the pendulum bob a bit bigger around to give it enough mass.

On the other hand, just like mounting it on the wall first to be sure it works, you may want to make the pendulum exactly as described in the instructions just to be sure of how it works before customizing. They can be tricky because what you are trying to do is get the center of momentum, which is similar but not exactly like the center of gravity, to be a certain distance from where it's hinged. If you just used a straight rod with no bob, the center of momentum would be at the exact center of the rod. Adding that mass to the bottom shifts it down. Once you get the center of momentum to be about the center of the bob, making the bob heavier doesn't change the speed of the pendulum, it only makes it swing out further. This can actually make things worse if the increased swing distance makes the pins push past the extents of the escapement.

Does your head hurt yet?

iSawitFirst, I went to the link you embedded, but only found a post on turned pendants for necklaces. Was the thought to use this idea to turn a “bob” to hang on the end of the pendulum rod? Please understand, I know little to nothing about pendulum clocks or clocks in general for that matter.

I read what Mechanologist said. Based on his comments on the pendulum bob, I have a question or two for you and Mech. Just trying to learn something here.

I’m not sure, but if you drilled a hole all the way through diameter of the circular bob the same diameter as the rod, and put a set or thumb screw through the back of the bob, you would be able to move the bob up and down on the rod to control swing distance and if I understand Mech correctly, also the “center of momentum”. Does moving the bob up the rod increase the speed of the clock and moving it down the rod slow the clock speed down? Would this kind of adjustment be wanted for adjustment or is it being handled in some other part of the clock mechanism?

Mech talked about increasing the weight of he bob by increasing its diameter. If you wanted to kept the diameter of the bob the same as planned, couldn’t you use a denser wood? Maybe Ipe, lignum vitae or some other dense wood? I’m guessing that finding a beautiful or matching grain pattern may be hard with a denser wood, but just a thought.

Also, if I understand correctly, the pendulum drives the escapement (I think that’s what it is called), which controls the rate of movement of the clock hands. Yes/No? If that’s then case, then what is driving the gears themselves? I didn’t see a motor. Isn’t there some sort of weight needed to pull down on say a drive gear to move the other gears?

I hope I’m not sounding too dumb here. I'm still trying to understand the terminology in this post.

[iSawitFirst]

Onboard,

All great questions. The pendant thread was referred to as an example of turned pieces that could be adapted to become the pendulum. The pendulum will have a hole through it top-to-bottom and a threaded rod inserted and attached to the pendulum shaft. A nut is used on the rod at the bottom of the pendulum to adjust the pendulum up and down. This regulates the speed of the clock.

There is a weight (5 lbs. or so) that drives the gears. The weight in the original design is a copper pipe filled with lead. I'll use either a wood tube filled with lead or brass weights.

Go to Boyer's site to see videos of Modern Times and all of his other designs. Some really creative stuff going on there.

I'm going to be really pressed for time to get this thing completed and have decided to go with the original pendulum design with an exotic wood. I've got some Marble Wood that I might use. Then, after its finished I'll experiment with other pendulum designs.

[Lawrence Brown]

Yep. iSawitfirst beat me to the reply: rod goes all the way through the bob and is moved up and down to regulate speed, heavier wood species = more weight, weights drive the clock.

[Onboard]

Thank you for the explanations. That helps considerably. Thank you Mech for the confirmation. I may understand this stuff yet, but that aside, I really like your design iSawitFirst!

Onboard,

All great questions. The pendant thread was referred to as an example of turned pieces that could be adapted to become the pendulum. The pendulum will have a hole through it top-to-bottom and a threaded rod inserted and attached to the pendulum shaft. A nut is used on the rod at the bottom of the pendulum to adjust the pendulum up and down. This regulates the speed of the clock.

There is a weight (5 lbs. or so) that drives the gears. The weight in the original design is a copper pipe filled with lead. I'll use either a wood tube filled with lead or brass weights.

Go to Boyer's site to see videos of Modern Times and all of his other designs. Some really creative stuff going on there.

I'm going to be really pressed for time to get this thing completed and have decided to go with the original pendulum design with an exotic wood. I've got some Marble Wood that I might use. Then, after its finished I'll experiment with other pendulum designs.

Yep. iSawitfirst beat me to the reply: rod goes all the way through the bob and is moved up and down to regulate speed, heavier wood species = more weight, weights drive the clock.

[nuetzij]

Hi Phil:

I noticed your Modern Clock picture, (at least the plans for the stand) on the internet, which brought me to this online post, (which looks to be about two years old now). I am also working on the Modern Times and would also like to mount it on a stand. Your plans, from what I have seen really do the clock justice. Would you be willing to share the plans of your clock base? I would be willing to purchase that if need be.

Well done on the design.

Joe