High-quality steel containing cobalt with a Rockwell hardness of up to 68-70 HRC (Rockwell Hardness Scale), which generally provides the best heat resistance, wear resistance, and long tool life.
The 3-step design can drill more efficiently into hard metal of stainless steel, aluminum, copper, plastic, and hardwood.
The drilling efficiency of this type of cobalt-containing drill bit is 3-5 times higher than that of ordinary drill bits. Despite the higher price, the cost per hole is lowest with a cobalt drill bit because it can make (drill) more holes.
The edge of the drill bit is sharp enough to cut through the metal material into iron filings instead of slowly grinding the material with a dull drill bit.
19 pcs 135-degree split-point drill bit set included: 1mm (length: 3.4 cm) 1.5 mm 2 mm 2.5 mm 3 mm 3.5 mm 4 mm 4.5 mm 5 mm (length: 8.5 cm) 5.5 mm 6 mm (length: 9 cm) 6.5 mm 7 mm 7.5 mm 8 mm (length: 11.5 cm) 8.5 mm 9 mm 9.5 mm 10 mm (length: 13 cm) [DIA 0.5 mm steps].