block 201 illustrated by a bracket comprising a wooden backing plate 204 and a facing 80 as described above to improve conformance of the screen 202 with the floor surface a compliant pad 206 may be placed between the facing 80 and the wooden backing plate 204 the sanding block is driven by a shaft 208 affixed to a flange 210 that is attached to the wooden backing plate with screws 212 the opposite end of the shaft 208 is affixed to a second flange 214 that is attached to riser 216 and a clutch plate 218 by screws 220 the drive shaft 62 of a floor machine 42 engages the clutch plate 218 to drive the sanding block 201 a shroud 222 with a skirt 224 forms a plenum 226 about the exposed periphery of the sanding block 201 a vacuum source not illustrated attached to the shroud draws air contaminated with dust from the plenum 226 a pair of bearings having flanged outer cases 228 and 230 attached to the shroud 222 with screws 232 permit the shaft 208 to rotate independent of the shroud 222 referring to fig7 the vacuum system 46 of the present invention is connected to the.