Double hammer

{{Short description|Forging implement used in metallurgy}}

A double hammer is a forging implement used in metallurgy. It operates on puddle balls and blooms by hitting both sides at the same time.{{Cite book|title=The Encyclopædic Dictionary|author=Robert Hunter|publisher=Cassell, Petter, Galpin and Co.|page=171|year=1883|url=https://books.google.com/books?id=YYIVAAAAYAAJ&q=%22double+hammer%22+music}} Double hammers are made of two blocks attached to rollers which facilitate opposing movement along a set of rails.{{Cite book|title=The Manufacture of Steel|author=Louis Emmanuel Gruner|author2=Lenox Smith|publisher=D. Van Nostrand|year=1872|page=[https://archive.org/details/manufacturestee02smitgoog/page/n65 55]|url=https://archive.org/details/manufacturestee02smitgoog|quote=double hammer metallurgy.}} Double hammers are normally operated by three people at a time: one holding the instrument in place and the other two moving the blocks back and forth.{{Cite book|title=A Manual of Mining|author=Eugene Benjamin Wilson|edition=4|publisher=John Wiley & Sons|page=[https://archive.org/details/amanualminingba00ihlsgoog/page/n650 628]|year=1905|url=https://archive.org/details/amanualminingba00ihlsgoog}}