Adjustable abrading tool

An abrading tool comprising:

• a threaded drive rod;
• a means for retaining an abrasive material about said threaded drive rod;
• an expandable support disposed about said threaded drive rod and proximate to the abrasive material, said support being dimensioned to brace said abrasive material, wherein said expandable support comprises at least one compressible O-ring;
• a means for expanding said expandable support, said means being disposed about said threaded drive rod, wherein said means for expanding said expandable support comprises at least two substantially rigid spacers, and wherein said spacers and said at least one O-ring are disposed about said threaded rod such that each of said at least one O-ring is disposed between two spacers;
• and
• means for setting a diameter formed by said expandable support, said means comprising:
• an adjusting knob comprising an inner bore and an outer surface, wherein said inner bore is threaded to mate with said drive rod and thread onto said drive rod in communication with said means for expanding said expandable support such that radial rotation of said adjusting knob in a first direction causes said expandable support to expand and such that radial rotation of said adjusting knob in a second direction causes said expandable support to contract, and wherein said outer surface comprising a plurality of marks disposed incrementally along said outer surface in positions corresponding to a plurality of diameters of said expandable support, and
• a sleeve substantially fixedly attached to said threaded drive rod, said sleeve comprising an outer surface dimensioned to fit within said inner bore of said adjusting knob and at least one mark disposed upon said outer surface of said sleeve.