Abstract: An uncoiler apparatus for uncoiling coils of wound sheet metal web material is provided with a spindle having an adjustable diameter. An inflatable member is wound about the spindle, and covered with a thin expansible coil. Upon positioning of a coil of wound sheet metal web material over the spindle, the inflatable member is inflated, and the expansible coil expands to engage the inner surface of the inner diameter of the coil of wound sheet metal web material. In an embodiment of the invention, the uncoiler apparatus is capable of being moved, in the direction of the axis of the spindle, and structures are provided for resisting static and dynamic pivoting moments imposed on the uncoiler by the weight and rotational mass inertia (acceleration/deceleration) of the coil.