Project
Details
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Date: Fall 2025
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Organization: Columbia University
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Objective: Learn proper machining procedures and techniques
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Key elements: Side blocks, threaded rod, linkages, end cap
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Role: Student
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Achievements:
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Successfully machined all parts on first attempt
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Assembled the jack and verified precise tolerancing
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Mini Jack
Machining
Notes
As a part of the mechanical engineering track at Columbia, I enrolled in an introductory machining course for the fall 2025 semester. The course was designed to allow students to reserve time in the shop, and machine parts of various materials and complexities on their own, using a variety of tools to do so. Due to my experience with the rocketry team, I began the course already having spent time machining. However, this was my first time using machines without a guide next to me, so I was excited to get fully trained, and be able to work on projects with even greater flexibility.
The first parts I made were 3D printed blocks which secured the top and bottom of the jack. The design was straightforward, with the only major decision being the choice to print the blocks on their sides, to ensure the through-holes were printed to tolerance.
The second set of parts I made were the geared linkages which would raise and lower the jack. These were machined using the mill, and were cut out of a nylon stock. The links could be described as 2 and a half dimension parts, as the stock was already the correct height, and no extra geometry needed to be cut in the z axis. The only operations these parts required both used the same endmill, cutting down the sides and then helixing in to make the holes.
The third set of parts, however, were more complex. These two were milled but needed a much more detailed set of operations. The side blocks were made out of acrylic stock, and due to the geometry in all directions, needed to be repositioned several times during machining. First, the parts were faced with an endmill, with an edge finder being used to set the dimensions. Next, the holes in the y direction were drilled using a drill attachment. The part was the flipped, with the cutouts being made using a smaller endmill, and the larger hole being made with a drill. In the end, this was the most time consuming part made during the course, but all of the care was worth it, as I completed all operations correctly on my first try.
The next two parts were made on the lathe. First, a threaded rod which would push or pull the linkages to adjust the height of the jack. This part was made of brass stock, which came with the threads already on. Thus, the only extra machining operation was to turn down the stock at one end, smoothing it to ensure only one block would interface with the threading.
The other part made on the lathe was the end cap. This cap was built from aluminum, and required both a cutting and facing operation to get the part to the correct dimensions, as well as several drilling operations. Both holes made along the axis of rotation were drilled using attachments on the tailstock, with those in the lateral direction being made using a jig and a drill press.
After completing the machining for all major parts, a rectangular base was laser cut out of acrylic, and an a handle was made out of a steel rod by attaching to a vice and bending it with a hammer. The jack was assembled and fitted with several mated bolts attaching the blocks and linkages together. The final product was tightly toleranced, and the jack was able to be raised and lowered with minimal resistance. By completing this exercise I not only was I officially trained to use the shop, but I got valuable practice using many different machines commonly found in most engineering settings, and built up more confidence in tackling solo projects.
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