This smaller size circle disc cutter set features 14 punches that range in size from 3mm-16mm.14 circular punches for cutting discs/blanks in sheet metal sizes-3mm, 4.5mm , 5mm, 6mm ,7mm ,7.5mm ,8mm,8.5mm ,10mm ,11mm ,12mm ,13mm ,14mm ,16mm.Jewelry Making Hand ToolPunches are machined flat and smooth on the cutting end To use the disc cutter, remove all punches from the block, and select the size punch you would like. Place your sheet metal in the slot and place your punch, sharp side against the metal, in the correct slot. Strike the beveled side of the punch with a heavy mallet until it pieces through the sheet metal. Be careful of your fingers and other items on your work surface. We recommend using a brass mallet (1lb. to 2lb. preferred) or dead blow to prevent damage to your disc cutter. You should also use Pro-Cut lube to reduce friction and wear on your punches. IMPORTANT: Always position a shim of the same thickness of the metal being cut directly across from the metal in the disc cutter block. This keeps the plates balanced and helps ensure a nice clean cut.