metal / machinery / abrasive tools / chemical action / plastics / abrasive media / hand-held tools / particular metal working technique / plural abrading devices / energy absorbing / unit manufacturing operations / electric control systems / servomotor systems / vacuum devices / abrasive tool / metal-working machines / rubber / tubular cutting tools / rotary tools / fluid-pressure servomotor systems / particular metal working techniques / condition responsive systems / safety systems / metal-working / metal article manufacture / abrasive media eg charging / metal shavings / metal working / safety devices / /