'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."

And [the] artisan encourages [the] {goldsmith}, [the] one who makes smooth with [the] hammer [encourages the] one who strikes [the] anvil, saying of the soldering, "It [is] good!" And they strengthen it with nails [so] it cannot be knocked over.