Gear's illustrated catalogue of wood and iron working machinery (1872)
A.S. Gear, Gear, A. S · Boston : Printed at A.S. Gear's printing office, 62 Sudbury Street · leaf 403
TAL FRAME CONSTRUCTION IN GRAND PIANOS. As regards the resisting strength of a grand piano, it was hitherto of no material consequence whether the iron framewas of cast or wrought iron. The total pull of the strings in a grand piano in different factories fluctuated between 25,000and 36,000 lbs.… … Figure Tl shows the new Centennial Grand overstrung scale, the patented design of the cupola iron frame, withthe new capo dastro bar for the reception of the steel-capped agraffes underneath, and serving as point of connection withall the other braces of the iron frame ; shows also the oblique bar,…
