A power tool having an elongated housing with a nose portion, an output shaft to which a cutting blade that oscillates through a small angle is attached, the attachment comprising, an accessory interface removably mounted to the nose portion of the housing and a depth guide attachment rotatably mounted to the accessory interface, the depth guide attachment further comprising a relatively thin body portion having a generally circular first opening with a center axis generally parallel to the output shaft, the body portion fitting on the accessory interface and being rotatable thereon and having a second circular opening transverse to the first opening center axis, a depth guide member adjustably mounted on the body portion and having an offset outer end portion, and a locking member configured to secure the depth guide member in a desired position.