500 holes have to be drilled into the iron frame. As precision is important, patterns fitted with hardened sleeves are used to ensure accuracy. They will later take up the agraffes, the wrest pins and the hitch pins.
At the foundry we see how the molten iron is being poured into the mould.
Here the iron frame for a concert grand is cast.
(c) 2008 Bluthner Polska sp. z o.o. Pianina i Fortepiany