Jamieson, Fausset and Brown on Isaiah 44:12

12. tongs--rather, "prepareth (to be supplied) an axe," namely, with which to cut down the tree designed as the material of the idol. The "smith" (Hebrew, "workman in iron") here answers to the "carpenter" (Hebrew, "workman in wood"). "He worketh it (the axe, not the idol, which was wood, not metal) in the coals," &c. The axe was wrought, not cast. The smith makes the axe for the carpenter.

hungry ... drinketh no water--so eager is he to expedite his work while the iron is hot. If the god were worth anything, it would not let him grow "faint" with hunger and thirst. Williams, the missionary, states that the South Sea islanders when they make an idol abstain from food and drink.