Grinder are Weaponsmithing Profession Assets that can be hired to perform various tasks from levels 7-13 in order to raise the character's Weaponsmithing level and produce weapons for the Great Weapon Fighter, Guardian Fighter, and Trickster Rogue. They can also be added to certain tasks that offer optional Person asset slots in order to reduce the completion time for those tasks.
At level 7, a Grinder can be acquired via a task that converts 4x [Smelter] to 1 Grinder. At level 13, 4 Grinders can be upgraded to 1x [Assistant Weaponsmith], which is needed for Weaponsmithing tasks at higher levels.
Higher tiered personnel, such as the [Assistant Weaponsmith] can be used instead of Grinders for tasks that call for them.
Grinders may be traded between players and bought or sold on the Tarmalune Auction House.