An electroplated diamond flat file with rectangular double-sided working faces. Standard grits are 100#, 120#, 150# and 180#, shank diameters Φ3, Φ4 and Φ5 mm, working lengths 50, 60 and 70 mm and overall lengths 140, 160 and 180 mm, all customisable. It is used for lapping, polishing, deburring, edge chamfering and shaping of low-iron metals and brittle non-metallic materials. High hardness, good wear resistance and heat dissipation keep the work surface from discolouring or picking up residue, with low noise and little dust.