The present invention relates to an apparatus for grinding and polishing a seam and more specifically to apparatus for grinding and polishing a welded seam between plates of stainless steel. Prior apparatus for such grinding and polishing generally consisted of a manually manipulated grinder and a separate manually manipulated polishing mechanism. Such apparatus required at least semi-skilled labor for its operation and compared to the apparatus of the present invention required a substantially greater length of time to complete the grinding and polishing operation. The apparatus of the present invention accomplishes the grinding and polishing function rapidly and effectively with a minimum of man power and with the use of operators having lesser skills than were required with prior devices.