Checking that the sides are parallel. In this process the frame maker would heat the frame over the Bunsen burner to warm the frame and make it more pliable to allow for small adjustments. After making these adjustments, the frame maker would pluge the frame into cold water after adjusting it to the correct fit. The photograph shows a bucket of cold water on the left. On the workbench you can see many tools such as pliers, files and joint screws (in the small box).