mid-1960s expanded on traditional coal waterjet cutting to determine ideal nozzle shape for high-pressure waterjet cutting of stone, and Norman Franz in the late 1960s focused on waterjet cutting of soft materials by dissolving long chain polymers in the water to improve the cohesiveness of the jet stream. In the early 1970s, the desire to improve the durability of the waterjet nozzle led Ray Chadwick, Michael Kurko, and Joseph Corriveau of the Bendix Corporation to come up with the idea of using corundum crystal to form a waterjet orifice, while Norman Franz expanded on this and created a waterjet nozzle with an orifice as small as that operated at pressures up to . John Olsen, along with George Hurlburt and Louis Kapcsandy at Flow Research (later Flow Industries), further improved the commercial potential of the waterjet by showing that treating the water beforehand could increase the operational life of the nozzle. High pressure High-pressure vessels and pumps became affordable and reliable with the advent of steam power. By the mid-1800s, steam locomotives were common and the first efficient steam-driven fire engine was operational. By the turn of the century, high-pressure reliability improved, with locomotive research leading to a sixfold increase in boiler pressure, some reaching . Most high-pressure pumps at this time, though, operated around . High-pressure systems were further shaped by the aviation, automotive, and oil industries. Aircraft manufacturers such as Boeing developed seals for hydraulically boosted control systems in the 1940s, while automotive designers followed similar research for hydraulic suspension systems. Higher pressures in hydraulic systems in the oil industry also led to the development of advanced seals and packing to prevent leaks. These advances in seal technology, plus the rise of plastics in the post-war years, led to the development of the first reliable high-pressure pump. The invention of Marlex by Robert Banks and John Paul Hogan of the Phillips Petroleum Company required a catalyst to be injected into the polyethylene. McCartney Manufacturing Company in Baxter Springs, Kansas, began manufacturing these high-pressure pumps in 1960 for the polyethylene industry. Flow Industries in Kent, Washington set the groundwork for commercial viability of waterjets with John Olsen’s development of the high-pressure fluid intensifier in 1973, a design that was further refined in 1976. Flow Industries then combined the high-pressure pump research with their waterjet nozzle research and brought waterjet cutting into the manufacturing world. Abrasive waterjet While cutting with