Chapin Machine Company
New Hartford, CT - The incorporation of the company was approved 7/15/1870 and the principals are Phillip E. Chapin, Edward M. Chapin, C. C. Goodwin, J. L. Purinton, W. H. Bushnell, and Marshall Jewel. Here are the articles of incorporation. By May, 1884 the factory appears to have been put up for sale.
This link to The Clamp Guy's website lays out the back story of the Chapin Companies. We are unsure if the companies in this article relate to Chapin Machine, except to say that two of the sons were co-founders.
W. K. Fine Tools has an even more extensive history. Be sure to note that there are 5 pages to read and browse pictures.
Daniel S. Coe Patent #140,404 - Improvement in Vises - Assigned to Chapin Machine Co. 7/1/1873