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The Crafting tutor (named Cadmus) is one of the several tutor guides stationed in Lumbridge. He provides different information about Crafting depending on one's Crafting level to both new and advanced players.
Cadmus gives players different information at level 1, 18, and 30 when spoken to.
He can be found in a room on the 1st floor[UK]2nd floor[US] of the Lumbridge Castle containing a spinning wheel.