concrete mold 3d model

A hollow cylindrical bowl-shaped mold for casting concrete, open at the top, with a flat closed bottom. Outer diameter 318 mm, wall thickness 4 mm, total height 40 mm. Flat bottom 5 mm thick. In the center a vertical cylindrical sleeve: inner diameter 56 mm, outer diameter 64 mm, height equal to the wall height, open at the top and bottom. The cavity between the central sleeve and the outer wall is open at the top, empty, meant to be filled with concrete. A small stepped lip (2 mm step, 3 mm depth) runs along the top outer rim. No texture, no logos, no text, no handles. Smooth surfaces, uniform wall thickness, watertight, manifold, 3D printable.