In 1895, the piano department was completely reorganized by Richard W. Initially they built only upright pianos featuring a patented method of tuning and maintaining string tension which they marketed as the screw stringer and intended as an improvement over the traditional system with tuning pins. Mason & Hamlin began manufacturing pianos in 1883. Mason & Hamlin supplied organs to several prominent composers, notably Franz Liszt, whose name the company applied to their patented selective sustain mechanism for organs comparable to the sostenuto in pianos. By the early 1870s they were considered the largest and most important manufacturer of reed organs, employing about 500 and producing as many as 200 instruments a week. This design placed the bellows vertically and underneath the reeds, and served as the model for the suction operated American-style reed organ. They originally manufactured only melodeons, but in 1855 introduced the organ-harmonium or flat-topped cabinet organ.

Mason & Hamlin was founded in Boston, Massachusetts in 1854 by Henry Mason, son of Lowell Mason, the American hymn composer and musical educator, and Emmons Hamlin, a mechanic and inventor who had worked for melodeon makers Prince & Co.

Mason and hamlin model a 805566