I know this is almost a year old and you probably solved it but I think the problem lies in the SetStaticDefaults because in 1.4 and onwards the Name and the Tooltip go in the localization folder/file and it should look like this Items: { FastPickaxe: { DisplayName: Sixty-Nine Thousand Four Hundred Twenty times 2 Pickaxe Tooltip: Even the Damage is worth it! Hopefully your PC won't crash... } essentially removing the need to have that function in the item file