The Metal Hammer is a Weapon in the Primitive+-DLC of ARK: Survival Evolved. It is an upgrade of the Wooden Club with twice as much torpor damage and higher durability due to a significant lower durability loss per hit.
The Metal Hammer works like a club dealing 1.6 times damage and 2.0 times Torpor. This means, a player needs only half as much hits to knock out creatures. Also, the torpor to damage ratio is higher.
Due to the low loss of durability a player can usually knock out several creatures before the Hammer breaks. Nevertheless, they should check the durability before trying to tame a creature, since the Hammer cannot normally be repaired in the player inventory but has to be taken to a smithy.