M35 Cobalt Drill Bit Set HSS-Co Length Twist Drill Bits with Metal Case for Stainless Steel Wood Metal Drilling. M35 Cobalt Twist Drill Bits Set. 1.5, 2.0, 2.5, 3.0, 3.2, 3.5, 4.0, 4.5, 4.8, 5.0, 5.5, 6.0, 6.5 mm. 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0mm. 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0mm. 13/19/25PCS + Metal Case. Cobalt drill bits require slow RPM when drilling metals. The suggested RPM is only for your reference. It may vary from different materials. You can start from a lower RPM and adjust it higher slowly. Once the bit can get into the workpiece. The adjustment should be stopped. 5% cobalt added for higher hardness and heat-resitance. The Rockwell hardness is up to 67. It can cut faster and has a long life, up to 12 times compared with the average HSS bit. The guiding separation point of 135° rapid cutting is self centering, which can penetrate quickly with less pressure. The straight handle can be firmly fixed and accurately centered, which is suitable for standard bit chuck and conventional round chuck. Efficient drilling without walking. Remove chips and particleseasier and faster. The lowest cost per hole drilled. Solid cobalt steel drill bit body can be resharpened. Drill directly to the size needed without pre-drilling. Heavy-duty fully ground body construction for minimal burr and accurate diameter. Bits for metal. Suitable for drilling non-heat treated metals, of which the hardness is less than HRC38, such as stainless steel, copper cast iron, galvanized pipe, iron, and aluminum alloy. Not suitable for hardened steel / high carbon steel. If penetration is not possible, try adjusting the speed. The drill can drill stainless steel, but processing stainless steel and other high hardness of the workpiece, it is recommended to be fixed on the drilling machine or platform type machine, the use of electric hand drill is prohibited, because the artificial use of electric hand drill is easy to shake, resulting in insufficient processing accuracy Or the bit gets dull or even breaks. The bit and the workpiece to be processed must be fixed or clamped. Generally, the rotational speed is less than 2000RPM. The larger the diameter of the drilling hole, the lower the rotational speed. The harder the material is, the slower the speed is required, and the more durable the cutting fluid is recommended. Can dry cut stainless steel and other high hardness metal, but continuous uninterrupted work is best to add water or coolant cooling, prolong the life of the product. 13 / 19 / 25PCS. M35 Cobalt Drill Bit Set.