Making a Pattern : Find the Frustrum of a Cone

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Sara, here

Custom orders are just that: totally custom. This means when people want something that is a size I’ve never built, or that Bob has already tried, or an item never before created, there is a lot of work to be done, which mostly takes place on the counter with a couple tools from high school geometry class and the backside of wrapping paper so I have the 1”x1” squares.

To make a pattern, first one needs the final dimensions. The easiest shapes are cylinders. The hard ones are anything that’s slanted and sloped.

When making a pattern for a cone, one must find the frustrum of a cone in order to properly account for the arc of the pattern, the amount of material needed, and also to add a bit more on all edges for seam allowances, later burring and wiring of tops and bottoms. Basically, it’s a lot of math. I’m not very good at math, so I’m thankful for calculators.

To find the frustrum of a cone for any slant-sided mug, bowl, kettle, teapot, or the like, you will need the following materials: large 3ft x 2ft paper or a roll of wide paper (I do like using the 1” square backs of wrapping paper), a protractor, a long ruler, a very large compass (or a long stick with a pencil on one end, and a sliding pencil on the other end), pencils, a calculator, the finished dimensions of the piece you’re making (as well as knowledge of what seams you’ll be using and their measurements, and the gauge of the wire you’ll use for any finishing/wiring), spray glue, and a large piece of tinplate.

Using this formula, so awesomely provided by Bob, create your cone pattern! (Click on the “Creating a Pattern for a Cone” link.)

Once you have it, cut it out of the paper and spray the glue adhesive on the back and place it on the tin, smoothing it out completely flat. Then, cut the pattern out of the metal as well. On the paper, you can write the name of the pattern, dimensions, and any other formula you’d like to recall about the pattern for later (size of finished base circle, seams, etc).

You now have a re-usable custom pattern for a taper vessel! Now…it’s possible to get building that cookware!

I’m also in the throes of trying to design tin-lined copper baking sheets. This should be interesting!!

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