The coupler is cast as a cluster of six couplers in a single casting. During casting the molten metal flows through the down sprue, into the runners and through the risers into the cavities.

After the casting is removed from the flask (the box which holds the sand mold) and cooled , the rough casting is cleaned of adhering sand in the “shake-out” process.

• The “shake-out” machine is a mechanical shaker. The casting sits on a steel screen and is vigorously vibrated to shake off the molding sand.

If the rough casting cluster rests on the coupler tabs in the “shake-out” machine, the tab edges will be abraded and damaged.

The couplers tabs can be protected during shake-out by sizing and positioning the risers so that the cluster rests on the risers, not on the tabs, during shake-out.