Olde-worlde Weight Clock - Revised

thingiverse

This appears to be a project guide for building a mechanical clock using 3D printing. Here is the text with minimal formatting: Once the escapement shaft is fitted add the pendulum arm. Now that the clock body is assembled it's time to build the pendulums. The two pendulums consist of two half hemispheres glued together with an M14 nut inside and paperclip loops. These should be printed with supports. Once the supports have been cut away, unfold and cut two paperclips off at 30mm. Fit the paperclip loop through the two holes in the top of the pendulum housing and bend the ends over. Push the bent over ends of the paperclips into the grove, splash some epoxy around and glue both haves of the pendulum over the M14 nut. Building the counterweight is straightforward, simply scale the STL file to fit your nut diameter, then add 7 M14 nuts and glue the lid on. Building the main weight is the same process, simply scale the STL file to fit your nut diameters, add the nuts and epoxy the lid on Before finalizing the clock decided that the clock face looked a little bare, so I printed out some numbers 0.3mm in thickness and stuck to the face. You can design your own using any typeface you like be they numbers or roman numerals, you could even write your numbers on by hand with a marker. The clock is completed by refitting the face, attaching the pendulums to the pendulum arm and mounting the weights and counterweights using a piece of standard blind cord. The escapement shaft should be suspended by a length of cotton so as to reduce any points of friction. The main weight should sit to the left, with the counterweight to the right. To rewind the clock simply pull the counterweight down, the ratchet will prevent the clock mechanism from running backward or being damaged. To calibrate the time simply move the pendulum weights along the arm until you find a position that keeps reasonable time. Obviously this won't keep perfect time, but with proper calibration it can come close. Duration: The project will take about 40 hours to print at 50mm/s. and will need to be printed in 3 to 4 batches. Filing, cleaning and inspecting the gears and bearing surface will take about an hour to complete, but is essential for the smooth running of the clock Construction should take no more than 2 hours with most of that time being spent gluing the numbers to the clock face as well as assembling the weights and pendulums. Preparation: After the parts have been printed they should be carefully cleaned with a sharp hobby knife and a file so as to ensure that there are no lips or excess plastic on any of the gear teeth or bearing surfaces. The list of printed parts is: Chassis front. Chassis back. Minute gear carrier. Escapement wheel carrier. Clock face. Main shaft. Main shaft ratchet pulley. Main shaft minute gear. Counter-shaft. Minute hand gear. Hour hand gear. Escapement wheel shaft Escapement wheel Escapement shaft Pendulum arm. 2X Pendulum tops 2X pendulum bottom Main weight. Main weight top. Counterweight. Counterweight top. Minute hand. Hour hand. The non printed parts are: 2x paper clips. 4x 12mm countersunk head timber screws. 5 Minute epoxy glue. 4x M20 stuctural nuts 9x M14 nuts References: The best recourse would be the prescribed classroom physics book, as this will include all of the concepts at work within the clock in a format that the students are familiar with. Wikipedia has some good explanations of the forces at work https://en.wikipedia.org/wiki/Moment_of_inertia https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion https://en.wikipedia.org/wiki/Kinetic_energy Rubric & Assessment: By the end of the project: Did the student successfully print all clock components for the model? Did the student assembled the project according to instructions resulting in a working clock? Did the student experiment and calibrate the clock by changing the pendulum positions? Did the student develop an understanding of the principals at work within the clock? Did the student develop an understanding of Newton's laws of motion? Did the student understand the concept of kinetic and stored kinetic energy? Does the student understand how to read the time?