Crafted for demanding professionals, this premium hole saw combines a cutting edge of hardened high-speed steel (HSS M35/M42, HRC 62-64) with a resilient carbon steel body, fused via vacuum brazing. This robust bi-metal construction delivers exceptional sharpness and longevity, resisting fracture under stress. Its scientifically ground teeth with optimized geometry ensure smooth, low-resistance cuts in metals, wood, and plastics, maintaining high performance for over 90 hours of use.
The blade runout ≤0.05mm, the hole diameter tolerance ≤±0.1mm, ensuring that the drilled hole is round and smooth, with no burrs and high perpendicularity (≤0.03mm/m), no need for secondary polishing, suitable for general precision installation scenarios such as electrical, plumbing and hardware.Versatility: Available in multiple specifications (diameter 12mm-250mm), suitable for drilling holes in mild steel, stainless steel (≤3mm), aluminum alloy, copper, brass, plastic, plywood, MDF and other materials. It is widely used in home decoration, electrical installation, automotive maintenance, mechanical processing and daily DIY operations.
M42 Cobalt Bi-Metal Construction – Features high-speed steel with 8% cobalt for superior hardness, heat resistance, and long life
when cutting stainless steel, hard metal, and abrasive materials.
Versatile Cutting Range: 14 to 210mm – Covers most hole sizes
needed for industrial, electrical, plumbing, and general construction tasks. Ideal for stainless steel, metal sheet, wood, and
plastic panels.
4/6 TPI Variable Teeth Design – Alternating teeth per inch (TPI) ensure smoother cuts, reduced vibration, and
faster chip removal across a wide range of materials, improving performance and tool longevity.
Dual Thread Sizes for Arbor Compatibility –
• Dia. 14–30mm: 1/2"-20 UNF rear thread (fits small arbors)
• Dia. 32–210mm: 5/8"-18 UNF rear thread (fits heavy-duty big arbors)
Fully compatible with standard arbors and pilot drill systems for both DIY and industrial users.
Ready for Power Tools – Designed for electric drills, cordless drills, and drill presses. Ideal for professionals needing high-performance hole cutting tools for demanding metalworking applications.
M3 vs M42 Bi-Metal Hole Saw Cutter – 5 Key Differences
Material & Composition
M3 Version: Made from M3 high-speed steel, ideal for general-purpose cutting with good wear resistance and toughness.
M42 Version: Made with HSS containing 8% cobalt, offering superior hardness and heat resistance for cutting stainless steel and hard metals.
Cutting Performance
M3: Suitable for wood, plastic, aluminum, and low-to-medium hardness steel.
M42: Optimized for high-efficiency cutting in stainless steel, alloy steel, and abrasive materials.
Durability & Heat Resistance
M3: Durable for light to moderate-duty tasks; performs well at standard drilling speeds.
M42: Excellent durability and maintains hardness under high temperatures — ideal for extended and intensive drilling.
Thread & Arbor Compatibility
Both:
14–30mm: 1/2"-20 UNF thread (small arbors)
32–210mm: 5/8"-18 UNF thread (large arbors) Fully compatible with standard pilot drill and arbor systems.
Best For
M3: DIYers, light industrial use, electricians, and general contractors.
M42: Metal fabricators, HVAC pros, stainless steel installers, and heavy-duty industrial users

Product Features & Advantages
Engineered for Peak Performance
This drill bit excels in demanding applications due to its exceptional durability and precision. Its specialized composition offers outstanding resistance to both heat and abrasion, reliably operating in high-temperature conditions and providing a service life 2 to 5 times greater than standard high-speed steel tools. The cobalt-infused structure grants remarkable toughness, preventing edge chipping and maintaining integrity under significant mechanical stress. Furthermore, the tool's surface characteristics significantly reduce the tendency for workpiece material to adhere during the machining of sticky substances such as stainless steel, promoting cleaner bore surfaces and more stable cutting action. Every unit is manufactured with complete precision grinding, guaranteeing tight dimensional tolerances (h8/h9), an excellent finish on the machined hole, and a consistently sharp point geometry for immediate and accurate engagement with the material.
Insoul's Manufacturing Excellence
The exceptional consistency of our products stems from twenty-two years of dedicated manufacturing, which has cultivated deep insights and scaled CNC machining capabilities. This is reflected not only in every Insoul cobalt drill bit that undergoes rigorous quality inspection but also extends to our drill bits designed for impact drilling scenarios. It is this unwavering commitment to detail that sets our proprietary brand apart from generic alternatives in terms of performance standards.
Primary Material Applications:
- Stainless Steel: Ideal for grades 304, 316, 410, etc. Commonly used in food processing equipment, architectural fabrication, and marine applications.
- High-Temperature Alloys & Titanium: Essential in aerospace, automotive (turbo components), and energy sectors.
- High-Strength/Alloy Steel: Perfect for machining hardened steel, forgings, and high-tensile structural components.
- Cast Iron & Non-Ferrous Metals: Provides excellent life and finish in cast iron, bronze, and brass.
Frequently Asked Questions (FAQ)
- Q1: Are you a factory or trading company?
A: We are 22 years+ professional manufacturer in drill bit tools industry.Welcome to visit our company.We guarantee our products are factory price, very cheap and competitive.
- Q2: Do you provides sample?ls it free or extra?
A: Yes.We could offer the samples for free charge but do not pay the cost of freight.
- Q3: why your price is higher than other company?
A: Because we are doing our own brand:the quality of the products is absolutely guaranteed.
- Q4: What is the MOQ?
A: We have fixed MOQ for each of our products. But if you need less,it's ok,as we will change the price according to your quantity.
- Q5: What is your term of payment?
A: 30% by TT in advance,and balance before delivery.
- Q6: How long is your delivery time?
A: Generally it is 7-10 days,If the goods are in stock.Or it is 20-30 days. If the goods are not in stock,it is according to quantity.
To meet diverse shipping and storage needs, we offer flexible and professional packaging solutions. Our standard packaging includes a durable white inner box combined with an outer kraft paper carton, ensuring optimal product protection during transit while emphasizing eco-friendliness and easy unpacking. For bulk orders or specific logistics requirements, we also provide palletized packaging services to enhance loading efficiency and shipment security, helping you streamline supply chain management. We are committed to improving product experience through thoughtful details, ensuring smooth operations for your business.