(57) The invention relates to honing, polishing, reducing, or otherwise abrading, in which improved means and methods are employed for abrasion of workpieces (10) in general, and at least selected internal portions (16) of workpieces (10) such as bores, passages, and cavities in particular. In general, the abrasion is accomplished by the use of a flowable abrasive medium (18), with particular embodiments using a visco-elastic, rheopectic abrasive medium.
The abrasive medium (18) is in the form of a plastic or semisolid matrix containing abrasive particales (120) distributed substantially uniformly throughout the matrix. The matrix transports the particles (120) through or across selected portions of a workpiece (122) being reated in order to permit the abrasive particles (120) to remove upraised metal and to round or radius comers as it passes, or to otherwise uniformly remove or finish these portions. Uniform distribution and maximised abrasive effect of the particles (120) is obtained by use of the matrix which also provides a relatively firm backing for the abrasive when the medium is subjected to high pressure.