Miller Electric Mfg. Co. ( designed its inverter-based Spectrum 1251 air plasma cutting and gouging system for hand-held and automated cutting. It severs 1.75-in.-thick steel and has a rated cutting capacity of 1.25-in. Rated capacity is the speed at which an operator achieves a smooth, steady cut at 10 in. per minute (ipm) using a hand-held torch. On 0.75-in steel, it cuts at 25 ipm.