We were all led astray by our typical connotation of a hammer.  There are
other types of hammers in a piano, as shown here -

https://www.bonanza.com/listings/Piano-Hammer-Head-Smoothing-Iron-Piano-Voicing-
Tool/1271947255?goog_pla=1&gpid=177431040541&keyword=&goog_pla=1&pos=&ad_type=pl
a&gclid=Cj0KCQjwtvqVBhCVARIsAFUxcRvZPVtKiJ_oeuOQt4KDhEoNr89fjWvxjPRa9-He6WXa8OZ4
fUM3eskaAqp_EALw_wcB


Yikes!  This one should work, too.

Phil

http://tinyurl.com/mr3k43hm