Workers in metal (6)
I believe the answer is:
smiths
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">workers in metal</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for smiths that I've seen before include "They make things in metal - horseshoes?" , "common names" , "Workers in metal" , "They make things in metal, may be black" , "We forge" .)