The ax head - literally, as in the margin. The Jews used iron for the heads of axes at a very early date (see Deuteronomy 19:5). They probably acquired a knowledge of the smelting process in Egypt, where iron was employed at least from the time of the third Rameses.
Related Commentaries of 2 Kings 6:5
2 Kings 6:5
5 But as one was felling a beam, the axe heada fell into the water: and he cried, and said, Alas, master! for it was borrowed.