What tool is used to crank a palate widener?

Palatal expander. Either a fixed (cemented) appliance or a removal one are orthodontic devises used to widen the palatal arch. A key is typically used to turn the expansion screws to the desired width.
Wire Key. The dentist that applied the palatal expander gave you the tool. Its a wire that inserts into a slot/hole that enables you tjo turn the screw to a more open/wider position. If you need another call your orthodontist for help.
A key. There is a key tool that is used to turn the palatal expander in small incremental movements. This will slowly expand the width of the upper jaw bone.
A key. A key looked like a small rod (1.6mm diameter) inserted into a small hole in the middle of the appliance and push inward to expand the palate. Try to avoid retract the key outward since this will reverse the expansion.