13-Piece M35 Cobalt Drill Bit Set, Metric Sizes 1.5mm to 6.5mm, 5% Cobalt HSS for Stainless Steel, Cast Iron & Hard Metal, Fully Ground 135° Split Point with Storage Case
Description
- PREMIUM M35 COBALT STEEL – Crafted from High-Speed Steel containing 5% Cobalt (M35 Grade). This hardened alloy ensures superior heat resistance and durability compared to standard HSS bits, measuring up to 67 Rockwell Hardness. Ideal for drilling through tough, high-tensile materials like stainless steel, cast iron, and titanium alloys.
- PRECISION 135° SPLIT POINT – Features a fully ground 135-degree split point geometry that self-centers immediately upon contact. This active cutting tip penetrates faster with less pressure and eliminates "walking" or wandering across the work surface, removing the need for a pre-punch.
- 13-PIECE METRIC SELECTION – Includes a carefully selected range of metric sizes for precision work: 1.5, 2, 2.5, 3, 3.2, 3.5, 4, 4.5, 4.8, 5, 5.5, 6, and 6.5mm. Note: Includes useful intermediate sizes 3.2mm (approx. 1/8") and 4.8mm (approx. 3/16") for specialized fitting requirements.
- EFFICIENT & CLEAN DRILLING – The fully ground dual twist flute design ejects chips rapidly, reducing friction and heat accumulation. This preserves the drill bit's life and ensures smooth, accurate holes without burrs, even during heavy-duty continuous use.
- ORGANIZED STORAGE – Comes packed in a labeled, durable plastic index case (marked with HSS-drills). The inner holder tilts out for easy access and keeps bits organized by size, making it perfect for transport to job sites or keeping your workbench tidy.
M35 Grade Cobalt Steel
Cobalt drill bits are not made of pure cobalt, but rather a steel alloy with certain percent cobalt. The 5-percent alloy is known as M35 grade. The cobalt increases the strength of the steel and makes it more heat-resistant.
135 Degree Split Point
The flater the drill, the smaller the chip width. This means less force required to remove metal, compared with lower angles like 90° and 118°. This is important on hard stuff, because your power requirements are already more than mild steel, so making the chip load less helps. It also reduces heat since less surface area is generating the cut.
Lowest Cost Per Hole Drilled
Cobalt drill bits are more expensive than other drill bits, but if you regularly drill through metal, they are a good investment since they tend to last longer. With an extended tool life, Migiwata cobalt drill bits will give you the lowest cost per hole drilled.
For Drilling Stainless Steel
This set of Migiwata M35 cobalt steel drill bits are particularly successful in cutting through hard metals such as stainless steel and cast iron, although they can be used for softer materials, too.
Tests shows that the M35 cobalt steel drill bits can penetrate a 5mm-thick 304 stainless steel plate in 5 seconds.
Not for Hardened Steel
M35 grade cobalt drill bits are NOT suitable for hardened steel, high carbon steel and heat-treated steel. Please buy carbide drill bits to drill these materials.
Cooling Liquid Required
Please use with cooling liquid to prolong the working life of the drill bits and to avoid overheating and breakage.
About Breakage
It's a common sense that harder stuffs are more brittle. While the 5% cobalt makes the bits much more durable as well as giving them an abrasive quality, it also makes them more brittle than ordinary HSS bits.