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This is 1937 mechanical drawing of a 1-gallon Medalta crock lid. Medalta Potteries manufactured crocks, on a large scale, from the 1920s on. In this example, I first imported the drawing as a canvas into Fusion 360, sized it and then positioned it so the center of the knob was at the origin point. I then traced the lid outline to create a sketch. Finally, I revolved that sketch to create the 3D lid. This was part of a project to enable a potter to make lids to fit the old crocks.

This picture has its own page with more detail, click here to see it.
No molds have survived so we are going to start from scratch. We will use Fusion 360 and 3D prints in PLA to create a block mold to make a rubber case mold. Learning to draw this rewarded me with some new 3D drawing skills. The geometry of the lip is challenging. It appears the piece will need to be cast with a full top and the lip shape and pouring hole cut manually (as was done originally at Medalta Potteries). I will likely have to create a 3D-printed PLA template as a cutting guide to get the lip contour more correct and consistent than they were able to do. Although not on the original, we are going to include a foot ring for easier glazing and better stability during forming and firing.

This picture has its own page with more detail, click here to see it.
These were used in the early 1900s to make crocks up to 60 gallon size in the Medalta Potteries factory in Medicine Hat, Alberta, Canada. The metal barrel was fitted with a wooden base, then lined with paper. Then the clay was rolled up the side and surface finished. The barrel was then dropped down into the false floor and the crock removed.

This picture has its own page with more detail, click here to see it.
The need for molds at the emerging Medalta Potteries project was the incentive to produce these beanpot reproductions. This was the 1990s, it was also an early opportunity to introduce digital technologies into the jigger mold and template making processes. I converted to vector graphic mechanical drawings, this enabled quicker redesign cycles to perfect the molds (especially the handle molds). These were also an enabler to showcasing Plainsman Clay's Alberta Slip glaze material (this glaze is 100% of that material).
| URLs |
http://medalta.pastperfectonline.com
Medalta Collections Database at PastPerfect - Search for the word "drawing" to see the mechanical drawings for hundreds of pieces |
| Glossary |
3D Design
3D Design software is used to create dimensionally accurate objects by sketching 2D geometry and transforming it using tools to rotate, extrude, sweep, etc. The software generates the polygon surface. |
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