Metallurgy Core adds the Stone Crusher, allowing the player to smash ore into Dust. By crushing into dust you increase your ore yields by 2x and you can mix dusts to make alloys.
If you have Metallurgy Base Metals installed, you get access to an array of new metal crushers that work faster and are more fuel efficient. You upgrade a certain crusher by putting it in the middle of your Craftingtable Grid and encircle it with eight Metal Ingot of the next tier.
The tiers are so far: Stone -> Copper -> Bronze -> Iron -> Steel
[Beta Version 2.0.0b] In the first Beta-Version of Metallurgy 2 crushers other than the Stone Crusher are only available through Creative Mode, the /give command, or inventory editing. It only works with M2-Ores (also the Vanilla ones, that are changed by the mod) and as of yet will not crush or be crafted with Ores from other mods, regardless of Ore Dictionary usage.