Steinway Double Iron Upright #17404

For a time Steinway made these "double iron" pianos both in a grand and upright version. The soundboard must be slid in between the two layers of cast iron plates. The three quarter plate open faced pinblock has trouble staying put since all there is to resist the great pull of the piano strings are some lag bolts. The strings win the tug of war eventually. George Steck built an upright with a sandwiched pinblock reminiscent of this double iron.