Selection Advice Views: 31

90 degrees is the metric ISO/DIN standard for M3-M12 metric countersunk screws, used across most of the world including China and Europe. 82 degrees is the US ANSI standard for #4-#12 and 1/4-inch to 1/2-inch imperial countersunk screws, used in North America (US, Canada). How to choose: 1. Check the screw - M-prefixed uses 90 degrees, # or inch sizes use 82; 2. Check the export destination - North America uses 82, elsewhere 90. Note: 90 and 82 degree countersinks look alike and are easily mixed up - store them separately, label them clearly and confirm the angle before use. A mismatched angle causes screws that will not tighten, protrude above the surface or sink too deep.