Johann Hinrich Klapmeyer likely learned the trade from his father Johann (Jean) Werner Klapmeyer, who was a journeyman with Arp Schnitger and was involved in the construction of the organ in Wittmund, among other projects. In 1729, he acquired citizenship in Glückstadt and worked there as an organ and instrument maker. Additionally, he ran an inn with a tavern. He became embroiled in a dispute with his competitors Lambert Daniel Kastens and Johann Dietrich Busch, who operated a workshop in Itzehoe. After petitioning the Danish king five times, Klapmeyer finally received the coveted organ-building concession for Schleswig-Holstein in 1735, valid for his lifetime. In his later years, he suffered from poor health and focused on running his tavern. His journeyman, Johann Joachim Maaß, took over the organ work. After Klapmeyer's death in 1758, his widow was granted the privilege to commission Maaß for the work. In 1763, she transferred this privilege to him.

A descendant of the same name, Johann Hinrich Klapmeyer (1724–1792), possibly a grandson, was based in Oldenburg (Lower Saxony) and built and repaired instruments in the organ landscape between the Elbe and Weser rivers.

https://de.wikipedia.org/wiki/Johann_Hinrich_Klapmeyer_(Orgelbauer,_1690)