It's like a machinist trade. I go to the oil companies, cement plants , fertilizer plants, steel mills, paper mills , aluminum plants, and about any plant in the nation that has a kiln, cooler, mixer or what ever, and I resurface the face of wheels. Some are 30ft tall and 80 inches wide and turn around 1-6 rpms. Some are 700 ft long or like this one here im on is 100 ft and 12'ft wheels. I widdle them down with a 3000lb grinding machine I have a crane and some welders on site to put me up there with. So its kinda a skilled craft. 100 or less to cover the whole world and around 30 in the USA. There is 8 in our company, and we get called the most. We have offices in around 5 countries. I just turned down a vietnam job so I get punished cris crossing the states. Well I got 6 hrs to shower shave eat and sleep, so I am closin in a minute.....