An In-Situ Machinist in the context of on-site services specializes in performing machining tasks at the location of equipment, rather than in a traditional workshop. This role involves on-site machining, flange facing, milling, boring, drilling, and grinding, often related to maintenance and repair of large machinery like engines, turbines, and other industrial equipment. They are responsible for ensuring machinery remains operational, efficient, and safe by performing necessary repairs and maintenance directly on-site.