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Thread: Re-engineering a plant stand: a geometry/math/engineering challenge

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    Re-engineering a plant stand: a geometry/math/engineering challenge

    A lady wanted a plant stand. Sounds simple enough. She gave us this photo:
    F851EB6C-EB39-4F8C-A3A7-6A1FBF1EC291.jpg

    Look closely at those miters. They land on a crossmember, but not all of the crossmembers are supported. This did not seem right, so I looked something similar up online, and yep- they have mitered edges with a crossmember, and no support under some of the crossmembers.
    E1B89644-0629-40C3-B4D3-1DA875A3BD23.jpeg

    How does that middle shelf hold a plant on those mitered pieces? It makes no sense. Also, that thing looks pretty flimsy. It needs to be “Malcolmized.”

    The lady wanted four shelves, and for it to be 48”x35.5”. I am not sure why 35.5 and not 36, but that was the order. I sat down with my students and we re-engineered the thing to have supports for all the miters. We built a 90 degree frame, and then three ladder supports at 22.5 degrees each. We drew the thing out on the table and laid up the shelves on the drawing, and then used that to line up the legs as well. (This gave them a better visual and helped me better explain all the miters.) Two crossmembers held the legs at proper angles.

    Here is the layout
    3DFBD2CF-4A31-49A6-A1BB-96BBB6E8DA8F.jpg

    Here is the finished product
    3C5D0595-EE67-4BAF-88CD-33AA607D0CE3.jpg

    It isn’t as heavy as it looks. One person can pick it up, but two are needed to carry it just because it’s so awkward. This was a one-off, or else I would have built a jig to cut the slats and one for the supports. Now I wish I had built the jig, because this thing would sell, and it is a great geometry lesson for more advanced students. We built the whole thing in two days, which is 5.5 hours each day for the students. We spent about an hour the day before that ripping all the slats. Keep in mind this was teaching and engineering as we built it, explaining how to figure out angles, and letting students take turns making cuts and assembling, so it goes slower than just building it.

    We are a non-profit that teaches trades to at-risk youth. Selling what we make is part of how we keep the shop going. They really did a fine job on this one. Any feedback will be passed on to them.

    www.mybrothersworkshop.org
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