'Soldering' in the Bible

Now a certain man drew the bow {at random} and struck the king of Israel between the soldering of [his] breastplate armor. Then he said to the chariot driver, "{Turn around}; get me away from the [war] camp, for I am wounded."

The craftsman encourages the metalworker;the one who flattens with the hammersupports the one who strikes the anvil,saying of the soldering, “It is good.”He fastens it with nails so that it will not fall over.