The circular rim meets the box-shaped body through a band of small ribs, while raised pads surround the side openings. YTD formed these connected features together with the housing walls and base through silica sol investment casting. Their shapes were established in the wax pattern before being reproduced in carbon steel.

In the mould, the small ribs correspond to narrow channels for liquid steel. The pads and junctions introduce thicker areas that cool at a different rate from the surrounding walls. A casting layout for this geometry must fill the rib tips while keeping liquid metal available to compensate for contraction in the thicker regions. This supply of additional metal is called feeding. The same pour must form the small ribs and supply the heavier connections as they solidify.