Complex sentence: Sertco was among the first aerospace machine shops to use one-hundred 100 percent CNC machines, when manual milling machines were predominantly used.still the norm Customers Sertco worked with included Cessna, McDonnell Douglas, Boeing, the United States Department of Defense and others.
Split into simpler sentences: Sertco was among the first aerospace machine shops to use one-hundred percent CNC machines, when manual milling machines were still the norm. Customers included Cessna, McDonnell Douglas, Boeing, the United States Department of Defense and others.