Metric M42 8% Cobalt Drill Bits Independent Packaging of Each Specification for Stainless Steel and Hard Metal (3.5mm x 5pcs)

Product Advantages: (1) Sharp Edge starts drilling immediately with less force and eliminates "walking" across the work surface. (2) Holds up better than generic high-speed steel,Cobalt gives high-speed steel more heat and wear resistance. (3) This drill bits set is made of Premium Cobalt (80,000 dollars per ton).(4) The M42 metric cobalt drill bits can cut through Stainless steel and Hard metal,Hard wood, although they can be used for softer materials such as Aluminum,Plastic. Some Important Tips about drilling stainless steel and hard metal:     (1)Controling the drill speed from 200 to 1000 RPM would make it easier for you to drill holes on stainless steel. ________________________________                Stainless Steel                       ____________________________       Drill diameter               RPM             ____________________________       ≤5mm                       1000~700    ____________________________       5-10mm                     700~350     ____________________________       10-15mm                   350~200 ________________________________     (2)Add stainless steel tapping oil or engine oil to prevent the stainless steel from overheating and forming a very hard oxide layer.It also works adding some vinegar,soy sauce or water if you don't have engine oil.

• Premium M42 8% Cobalt Steel ,68-70 HRC (Rockwell Hardness Scale) ,Usually Give the Best Heat,Wear and Chip Resistance and Long Tool Life.
• Split Point Design for Cutting through Stainless Steel,Hard Metals,Aluminum,Plastic and Hardwood.
• This Cobalt Drill Bit is Typically Capable of Running Three to Five Times Faster.Despite the Higher Price,the Cost Per Hole When Using Cobalt Drill Bit Will be the Lowest,Since It Can Produce So Many More Holes.
• The Sufficiently Sharp Bit Edge Can Cut the Metal Material into Long Strips of Iron Chips rather than Slowly Grinding Throng the Material with a Blunt Drill Bit.
• Includes :M42 Cobalt drill bit 3.5mm x 5pcs ,135 Degree Split Point.