In 1910, he moved to Springfield, Vermont to work as a mechanical engineer for the Fellows Gear Shaper Company. He was already friendly with James Hartness, the president of the Jones & Lamson Machine Company (J&L), another company in town. In 1911, Flanders married Hartness' daughter, Helen. Shortly afterwards, Hartness hired Flanders as a manager of the department at J&L that built the Fay automatic lathe. Flanders redesigned that lathe to achieve higher productivity and accuracy. He became a director in 1912 and president of the company in 1933 after Hartness retired.