The Seth Thomas Type 89 movement is a robust and well-regarded mechanical clock movement widely used in many of Seth Thomas’ mantel and shelf clocks from the early 20th century to 1938. The movement was introduced in 1900 and became one of Seth Thomas’ most popular and enduring movements. There are several variants (89A, 89C, … More On My Workbench | Type 89 Movement by Seth Thomas and a Strike Side Issue