Drawing irons were once used to form (draw) iron, performing in earlier times the work of today's drawing dies. They were either made completely of steel (English solid steel irons) or featured only a steel covering. First the drawing irons were forged in hammer forges, then the drawing holes were added in a special operation by so-called hole makers using cold punching tools.
One drawing iron contained several drawing holes of conical shape (due to the wedging effect during forming).
Worn drawing irons were reconditioned by closing the old hole by hammering and then restoring the required dimension. Alternatively the old holes were used for a larger diameter.
See Also
Adapted from “"We do it straight" — Wire Straightening”, p. 73 (ISBN 3-00-005897-4).