Here is my custom sword class:

import com.terraweapons.main.TerraWeapons;
import net.minecraft.item.ItemSword;

public class TerraSword extends ItemSword {

    public TerraSword(String name, ToolMaterial material) {
        super(material);
        this.setUnlocalizedName(name);
        this.setCreativeTab(TerraWeapons.tabTerraWeapons);
    }
}

Here is my ToolMaterial code:

public static ToolMaterial material1 = EnumHelper.addToolMaterial("material1", 3, 100, 2.0F, 0F, 20);

And here I register my weapons:

public static Item weapon1 = new TerraSword("weapon1", ToolMaterials.material1);

I explain this here.