A mounting adapter for mounting a surface processing tool having a rotational or longitudinal axis to at least one spider arm of a rotatable spider assembly of a surface processing apparatus, the spider arm having a leading side and a trailing side as a function of the direction of rotation of the spider assembly. The mounting adapter has a first element for removably attaching the adapter to the spider arm and a second element positioned circumferentially offset behind the first element for positioning the rotational or longitudinal axis of a surface processing tool circumferentially offset behind the trailing side of the spider arm. In one embodiment, the first element is an elongate handle and the second element is a planar plate which extends generally perpendicularly from the handle between one end of the handle and a point intermediate the ends of the handle.