Spiral Bevel Co provides assistance in design of large spiral bevel gears. While designing of a large spiral bevel gear it is critical to optimize all the parameters of the gear on a computer model before producing the real gear. Large spiral bevel gears are very expensive to manufacture due to limited availability of the gear cutting machines. There are just 6 gear cutting machines in the US that can produce spiral bevel gears larger than 50" in diameter. Three 100-inch Gleason machines and two 80-inch Klingelnberg machines are located in Illinois and belong to two companies. One large 675 Gleason 100-inch machines is in operation in Texas. The six available machines are capable to produce one gear set a week each, which comes to total of 300 gear sets a year. In order to speed up production of the large gears the owners of Gleason and Klingelnberg spiral bevel gear machines use CNC milling for rough cutting of the tooth, so the gear generating machine cuts the gear faster. Rough cutting allows to reduce the cutting time for about 50%. However, the geometry of the CNC cut remains poor if DDS technology is not used. Also, without DDS technology, the rough cutting needs to be finished on gear machines if the gear requires hard cutting after case hardening.