Abstract: An extruder die assembly adapted for attachment to the output end of an extruder barrel. The die assembly includes an adapter member and a die head. The adapter member is attached to the extruder barrel, and the die head is pivotally attached to the adapter member by a hinge. The die head can be rotated about the hinge from a first, closed position to a second, open position. First and second clamp plates are slidably attached to the adapter member. The clamp plates are movable from a first, clamping position to a second, unclamped position, and have clamp fingers extending therefrom. The die head has clamp ears extending therefrom in a location such as to lockingly engage the clamp fingers when the die head is in its closed position and the clamp plates are in their clamping position. The clamp fingers and clamp ears are configured to lockingly engage each other by means of tongue and groove joints.