3d clock plans10/27/2022 ![]() ![]() There are two 18 tooth pinions on gear 4 with a friction fit to allow setting the time. Gear 5 and 6 form a secondary path for the minute hand to drive the hour hand. Each gear in the train rotates slightly faster, until it gets to the escapement rotating every 39.5 seconds. The weight shell has a pulley, so a 52" drop unwinds 104" of cord. Here is a diagram showing the clock gear connectivity and speed. The rest of the gears are labeled sequentially towards the weight drum. I suppose the pallet could have been called gear 0, but I simply call it the pallet. There are eight gear sets labeled mostly starting with the escapement labeled as gear 1. Let's start with the naming convention used when designing the clock. Here are some details about the clock design and gear ratios used. The pendulum rod was printed in two sections and epoxied together with a threaded rod sticking. It pivots on two small ball bearings with the grease removed to lower the friction. ![]() The pendulum is a two piece clamshell with a few pennies added for weights. The front and back frame sections just barely fit diagonally on the MK3 print bed. The same multi-layer technique is used to add gold highlights to the clock hands. The first few layers are printed tan colored with pauses for the ivory colored dial and black numbers. The front frame integrates the dial and numbers into a single 3D print. The support bar also includes a convenient location to store the winding key. This design could easily handle double the weight with no visible sagging. The top of the frame has a robust support bar to prevent frame sag from the heavy weight shell. Standoffs push the clock body away from the wall for pendulum clearance. The back frame integrates a metal keyhole hanger to hang the clock on the wall. The clock frame consists of two major components. I added steel bushings at several critical locations to reduce friction enough to use the 8 day gear set. Some of my initial experiments used a larger weight shell and a 3:1 divide ratio with only a 4 day run time. The weight shell holds 4.5 pounds of lead shot to provide just enough power to keep the clock running. Two gear sets divide this down to one rotation per hour of the minute hand. A 1" winding drum will only rotate once every 6 hours. A pulley doubles the length to unwind 13" of cord per day. An 8 day run time with 52" of drop means that the weight will drop 6.5" per day. A falling weight provides power to the minute hand which in turn pushes the pendulum. The final component of the gear train is the weights. This gives a balanced look but loses the ability to add a second hand. Three sets of gears with 54:12 ratios drive a 30 tooth escapement and a 17" pendulum with 5467.5 beats per hour. A traditional clock design with 60:8 and 64:8 gear ratios would need a 39" pendulum rod which seemed too long for this design, so I changed the gear ratios to allow for a shorter pendulum. This clock uses a deadbeat escapement designed in Gearotic. The constant rate is what helps the clock keep accurate time. I used a traditional Roman numeral dial for this clock.Ī pendulum swings at a constant rate depending on its length. The basic requirement is that the minute hand should rotate once per hour and the hour hand should rotate once per 12 hours. Most pendulum clocks share the same basic structure with slight differences in the gear ratios. The next step was to design the overall gear train. I printed the gears in gold colored filament to get them to look like brass. Smaller pitches were possible, but some of the teeth were slightly distorted. A 20 DP gear with 60 teeth will be 3" in diameter. I printed an assortment of gear sizes ranging from 10 dot pitch down to 40 DP and selected 20 DP as my favorite. They needed to be large enough to print accurately, but not so large to exceed the capabilities of my printer. ![]() One of the first experiments was to determine a good gear tooth size. Involute gear profiles were designed using Gearotic and imported into TurboCAD for final adjustments. I started with a basic sketch of the clock, then fit the gears so they would be relatively symmetrical. Designing this clock has been a spare time hobby of mine for the past 6-8 months. The challenge is to make everything work elegantly and accurately. #3d clock plans seriesA series of gears convert the pendulum motion into a display for the hours and minutes. A spring or falling weight provides energy to a swinging pendulum that swings at a constant rate. A pendulum clock is conceptually very simple. ![]()
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