From the OHS PC Database, derived from A Guide to North American Organbuilders by David H. Fox (Organ Historical Society, 1991) -

Succeeded Wisconsin Pipe Organ Factory; established by Bernard Schaefer in Schleisingerville {Slinger}, Wisconsin, c. 1910; succeeded by Schaefer Organ Co., 1920.

Sources:

• Cypher, 9/10:7.
• Diapason, May. 1929, 17.
• Organ Handbook (OHS Press 1984), 29.

From the OHS PC Database Builders Listing editor, Mar 15, 2016. -

In 1875 Bernhard built his first organ for St. Peter's Church in Schleisingerville [now Slinger, Wisconsin] and thus started the B. Schaeffer Organ Company. Bernard's eldest son John joined him in the organ making business.

In 1913 the name of the primary business was changed to the B. Schaefer & Sons Organ Co. John and his twin brothers Theodore and Joseph A. Schaefer who were born in 1887 also joined the business. In 1918 John died at the age of 52. Bernard suffered a stroke in 1914 from which he never fully recovered. He passed away in 1920. After Bernard's death the business was incorporated under the name of the Schaefer Organ Company.

Source:

• Larry Gundrum, Slinger historical album: Schleisingerville to Slinger, 125 years, 1869-1994 (Slinger Advancement Association, Slinger, Wisconsin, 1994).

For further information, see:
Schaefer Organ Company
Bernard Schaefer