Hellforge

A Hellforge is a crafting station that incorporates the same functions as a regular Furnace with the additional bonus of being able to smelt Hellstone into Hellstone Bars.

It is found in The Underworld and can be moved above ground. Hellforges in the Underworld require a 60% power Hammer or stronger (Meteor Hamaxe or better) or by destroying the blocks below it (which is the only way to obtain Hellforges if you don't have a strong enough hammer yet). Hellforges above the Underground layer can be moved with any Hammer.

On the console versions of the game the Hellforges are found directly above the Underworld and are not found within the underworld itself.

(Edit: I found aproximately 7 hellforges in the underworld on the ps3)

The Hellforge is 3 blocks wide, 2 blocks high, and must be placed on top of solid blocks or Wood Platforms.

Hellforges are commonly used to drain a large body of water or even oceans. To do so you have to dig a small hole (3 blocks wide, 4 blocks deep) under water and then close the ceiling. After that you need to drain the small hole of water, place a Hellforge at the bottom and pour a bucket of lava on it. Then you can destroy the ceiling to let the water drain. This is because the Hellforge prevents it from forming obsidian, so the water disappears.

History
Forge infernale