Clue: Players must support director that's to shape The Crucible's lead (3-4)
Answer: DIE-CAST
Explanation: Definition: to shape The Crucible's lead
 CAST(group of plays acting in a play or film) **placed below**(must support, in a down clue) [ D(abbrev. for "director") + IE(abbrev. for "id est"/that is/that's) ].
Defn: To shape a quantity of molten lead, the metal, by pouring it into a mould, after it has been melted in a crucible/a ceramic or metallic pot able to withstand high temperature.