Foredom AK8000 Cobalt Steel Step Drill Set, 10pcAK8000
Set includes: .5mm (A-8005), .7mm (A-8007), .9mm (A-8009), 1.1mm (A-8011), 1.4mm (A-8014), 1.6mm (A-8016), 1.8mm (A-8018), 2.0 (A-8020), and 2.2mm (A-8022). 1.2mm (A-8012), 1.4mm (A-8014), 1.5mm (A-8015), 1.6mm (A-8016), 1.7mm (A-8017), 1.8mm (A-8018), 2.0mm (A-8020), 2.1mm (A-8021), 2.2mm (A-8022) and 2.3mm (A-8023).
Drills are solid cobalt steel and outlast high speed steel (HSS) bits 15 to 1.
Drilling speeds should be between 500 and 10,000 rpm. All drilling should be done with a lubricant. The harder the material (metal) to be drilled and the larger the hole size, the slower the drill speed.
Material 1mm (1/16) Drill 2.35mm (3/32) Drill
Aluminum 7,000-8,000 5,000-6,000
Mild Steel 3,000-3500 2,000-3,000
Stainless Steel 1,000-2,000 500-1,000
Brass, Silver, Copper 5,500-6,500 4,000-5,000