Selection Advice Views: 28

Sizing principle: the countersink diameter should be 2-5mm larger than the countersunk hole so the full hole is cut in one pass. Recommended sizes for common screws: 1. M3: countersunk hole 6.5mm, use 8mm countersink (smallest standard); 2. M4: 8.0mm hole, use 10mm; 3. M5: 9.5mm hole, use 10 or 12mm; 4. M6: 11.0mm hole, use 12mm (most common); 5. M8: 15.0mm hole, use 14 or 16mm; 6. M10: 18.0mm hole, use 16 or 20mm; 7. M12: 20.0mm hole, use 20 or 25mm. Notes: 1. Do not oversize - bigger tools vibrate more and waste material; 2. Do not undersize - multiple passes lower efficiency and leave witness marks; 3. One countersink serves multiple hole sizes (e.g. 12mm handles M4-M6) as long as the hole is smaller than the tool; 4. Lihao Technology offers the full range: 8mm (5mm shank), 10mm (6mm shank), 12/14/16mm (8mm shank), 20mm (10mm shank), 25/30mm (12mm shank); 5. Special sizes are custom-made with 7-day delivery. See the M3-M12 countersunk screw hole size chart on the Lihao Technology website for the full table.