- Zodiac Quartz Wall Clock (Astrological Signs)
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- Astrological Clock Spiral Notebook for Sale by Clara Sandberg
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Show Basic Colors. Description Our spiral notebooks are 6" x 8" in size and include pages which are lined on both sides. Ships Within 2 - 3 business days. Similar Designs. Similar Designs More from Clara Sandberg. Additional Products. Spiral Notebook Tags spiral notebooks clock prague steampunk. Photograph Tags photographs clock prague steampunk. You could also use a CNC. I use a 1 RPM synchronous motor to drive my clocks. That makes the motor extremely accurate. Be careful. That said, using these motors is about as complicated as wiring a lamp socket.
If you are comfortable doing that with a little bit of soldering added in, then you are set. You can buy these on Ebay for pretty cheap but you have no guarantee on the quality and you have no idea if they were designed to run continuously. Cheap synchronous timing motors are not designed for continuous use and can overheat. However, I've run into a lot trouble trying to find reliable, slower synchronous motors. This is normal, but it should never get so hot that you cannot hold the motor in your hand. I also use a heat sink in all of my clocks that helps prevent the wood around the motor from getting too hot.
Some of my motors groan a little every once in a while. When the motor starts to fail it can make some really strange noises. I've had one running for about two years with no problems. All the same you should be prepared to replace your motor in the future: clocks can last forever but motors definitely can't. That said, the amount of load probably shortens the life of the motor. I've burned out recycled, slower motors on my planetarium.
This book is focused on building weight-driven wooden clocks and is a gem. Boyer's designs are stunning and he also sells plans on his website. Gears and Gear Cutting by Ivan Law. Life of James Ferguson, F. This book is available in full for free on Google Books. James Ferguson was an incredible horologist and all of his designs are described here. My Planetarium and Tellurion use gear ratios from this book - I just added gears for the clock and calendar.
To design a clock you need to understand the basics of designing with gears. Don't worry if this seems like an overload of information - it really is pretty basic once you get going. Gears are used to transmit power between one shaft and another. If Gear A is moving clockwise and it turns Gear B, Gear B will turn counter-clockwise the same movement is passed on but in the opposite direction. If you need gear B to turn in the same direction as A, a 3rd gear, or idler pinion , is needed. The diameter of the gear and the number of teeth are directly related to the speed of the gears.
The take home point is that there are two types of gears: cycloidal and involute. Both types of teeth allow the teeth to engage without locking.
Zodiac Quartz Wall Clock (Astrological Signs)
Improperly formed teeth will result in noise and a loss of efficiency in the gear train. Involute is the standard today and is most likely what your gear generator will be making. Pitch Circle or Pitch Circle Diameter, PCD : The imaginary diameter of the gear teeth and bearings in peripheral contact where the two gears will actually mesh. Imagine that you have replaced your gears with two circles that turn each other with friction - the diameter of these circles is the pitch circle diameter.
Swayed by common practice, I go with imperial. Once you pick a system be sure to be consistent. Pressure Angle: The angle on an involute gear between the acute angle formed between the line of action and the common tangent to the two pitch circles. You don't need to worry about the formal definition much - you just need to be consistent. A pressure angle of 20 is common.
Diametrical Pitch DP : The number of teeth divided by the pitch diameter. Two correctly meshing gears will have the same DP and pressure angle, see above. For instance, if you need two gears, one with 20 teeth and one with 10 teeth, and you choose a DP of 20 than the 20 tooth gear will have a PD of 1", and the 10 tooth gear will have a PD of 0. Center Distance: The center distance is equal to the sum of the pitch diameters of the two gears divided by two. Gear Ratio: The ratio of gear teeth required to reduce or increase the speed of the shaft. For instance, for every revolution of the 20 tooth gear, the 10 tooth gear will turn twice, and so the speed is increased by a factor of two.
What do you want your clock to do? The design elements are up to you and just about anything is a possibility:. I use a 1 RPM synchronous motor to run my clocks. OK, now we have some basic ideas about what we want to do and how we want to do it. For this step I will go through gearing a clock using some of Ferguson's gear ratios his clock designs are explained in detail in his biography and I used them for my first two clocks. In my next step I'll walk you through how to design your own gear ratios for orbital periods.
Remember to keep the direction of your gears in mind. A gear that turns clockwise will turn the next gear counterclockwise. Your hour and minute hand need to be clockwise and planets should turn around the sun counterclockwise. Any combination of gears that gets us to a speed reduction of 60 will work. For this clock we will use two gear sets: a speed reduction of 6 and a speed reduction of In general 8 teeth should be the minimum for your gears.
Fewer teeth and the gears just don't run well. That is a pretty easy speed reduction of In order to keep the hour hand going counter clockwise, we need to use 2 gear sets. I usually use reduction of 4 and reduction of 3. That is pretty steep but you can get there in all sorts of ways. Step 4 - Orrery: We'll use Ferguson's gear ratios for his orrery described starting on page of his autobiography. Ferguson walks through the calculations involved in coming up with his gear ratio in his biography.
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However, you can also develop your own gear ratios to approximate almost any number. I'll cover that in the next step and then we will move on to creating a model for our clocks. From the previous step it is clearly pretty easy to figure out how to achieve a speed reduction for just about any integer. To find those gear ratios you can use experts like Ferguson, you can use a computer program, or you can do it by hand using the Stern-Brocot method. Essentially the method is to approximate the gear ratio by trial and error, and it can be done very easily in an Excel spreadsheet. For example, let's calculate a gear ratio for the synodic month.
That comes out to a speed reduction of So the speed reduction we want is between 59 and So on our excel spreadsheet we start with the following:. The first line uses a gear ratio of The third number is the output speed of that gear ratio, or how long the synodic month would be if we used a ratio of We do the same thing for the second line and come out with a synodic month of 30 days. OK - looking at those two lines, it is clear that 1 is closer to our desired gear ratio. So we will add a line in between the first two lines and add the first two columns together, calculating out the third column as we did before:.
Now we basically just repeat that step over and over. Looking at those three lines, we know our desired synodic month period is between the first and second lines. So we would add a line between those and add the first two columns together, calculating out the third column again. You continue doing this until you get reasonably close to the output speed that you want and until you get a gear ratio that is easy to work with.
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For my synodic month I ended up choosing the : gear ratio which resulted in 1 day of error per years not bad! Using the least common denominator method remember your fractions? Isn't math fun? Remember, you do not need to do this to build your own clocks. There are tons of resources out there where people have already figured this stuff out. But if you master this tool you can figure just about anything out for yourself. Determine what diametrical pitch DP you want to use for each gear set for the teeth to mesh each set of gear must have the same DP.
The DP will basically determine the size of the gear and is entirely up to you. Just make sure the teeth are not too small or they will be fragile and impossible to cut. The larger the DP, the larger the gear and the easier the teeth are to cut. I try to stick between 9 and Set a universal pressure angle.
I use Just make sure it is the same for each set of gears. Use the involute gear tool to generate each set of gears. Set the keyway width and depth to 0.
Astrological Clock Spiral Notebook for Sale by Clara Sandberg
Calculate the center distance between each gear set. The MACC is available in two formats. Instructions for purchasing this clock plan can be found on this page: Masochist's Corner. Clayton Boyer Clock Designs. Frequently Asked Questions. Favorite Links. Other Designs, Not For Sale.
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