Punches_and_Dies

Depending on the type of material to be punched and the number of holes to be made, you can select your optimum clearance. The clearance indicated is the total clearance between punch and die expressed in a % of the thick- ness of the material to be punched. This is valid for round holes made in flat plate. Punch-to-Die Clearances Aluminium, Soft 1 - 3% 4 - 8% 9 - 15% 16 - 20% Aluminium, Hard 2 - 5% 6 - 10% 18 - 25% 26 - 35% Brass, 1/2 Hard 2 - 5% 6 - 10% 16 - 26% 27 - 34% Brass, Annealed 2 - 5% 6 - 11% 20 - 30% 30 - 42% Bronze, Comm. 1/2 Hard 2 - 5% 6 - 10% 20 - 30% 30 - 36% Copper, 1/2 Hard 2 - 4% 5 - 10% 16 - 24% 25 - 42% Copper, Annealed 2 - 5% 3 - 8% 16 - 20% 21 - 28% Lead 2 - 4% 4 - 10% 12 - 16% 16 - 20% Magnesium 2 - 5% 6 - 10% 12 - 20% 20 - 34% Stainless, Annealed 4 - 6% 6 - 10% 20 - 30% 30 - 45% Steel, Low Carbon 2 - 4% 5 - 10% 20 - 30% 31 - 42% Steel, High Carbon 5 - 8% 10 - 20% 21 - 34% 35 - 48% Recommened Total Clearance Expressed as Percent of Material Thickness Hole Characteristics that vary with Clearance Extremely Tight Clearance Normal Tight Clearance Recommended Ejector Clearance (Optimum) Loose Ejector Clearance (Longest Tool Life) 82 The Information given is for guidance only. Berger Tools acepts no liability