Shore durometer The basic test requires applying the force in a consistent manner, without shock, and measuring the hardness (depth of the indentation). If a timed hardness is desired, force is applied for the required time and then read. The material under test should be a minimum of 6 mm (0.25 inches) thick. The ASTM D2240 standard recognizes twelve different durometer scales using combinations of specific spring forces and indentor configurations. These scales are properly referred to as durometer types; i.e., a durometer type is specifically designed to determine a specific scale, and the scale does not exist separately from the durometer.
North Shore (Lake Superior) efforts, many of the forests along the North Shore are now protected from deforestation, but there is still a strong paper industry that relies on pulpwood. In 1855 when a lock system first allowed steamboats onto the lake, eastern tourists began to travel onto Lake Superior for recreational purposes. They would then canoe or be ferried from Duluth up the North Shore and would stay in hunting and fishing camps. In the 1920s, the North Shore highway was built, which helped make the North Shore accessible by land. At the same time commercial fishermen began to go out of business