3 tlg HSS Step Drill Bit Drill Set 4-12mm/ 4-20mm/ 4-32mm

3 tlg HSS Step Drill Bit Drill Set 4-12mm/ 4-20mm/ 4-32mm Dimension: 1:4 mm to 12 mm 9 steps (4mm 5mm 6mm 7mm 8mm 9mm 10mm 11mm 12mm) 7cm (L) 2:4 mm to 20 mm 9 steps (4mm 6mm 8mm 10mm 12mm 14mm 16mm 18mm 20mm) 7cm (L) 3:4 mm to 32 mm 15 steps (4mm 6mm 8mm 10mm 12mm 14mm 16mm 18mm 20mm 22mm 24mm 26mm 28mm 30mm 32mm) 10cm Note: When drilling the hardness and hole of larger diameter the bit must cool with cold water cool the drilling for 120 to 240 is extended for the processing of 6 mm and the plate the bits of high-speed steel material drilling 120/ drilling more than 20 mm drilling not more than 400 RPM and water cooling. Package: 3pcs hex HSS spiral groove stage drill with transparent plastic boxes set Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.