$19.66
A) Drill Diameter 4mm
B) Overall length 75mm
C) Flute length 43mm
Point angle 135 degrees
Frequently Asked Questions
What materials can this cobalt drill bit cut?
Our cobalt drill bits handle stainless steel, cast iron, hardened steel, alloy steels, aluminum, copper, and more.
What speed should I use when drilling metal?
Use our Speeds & Feeds Calculator to set the correct RPM. Running too fast will overheat the bit; slower speeds preserve sharpness.
Can cobalt drill bits be resharpened?
Yes — cobalt drill bits can be resharpened, giving you long-term value.
How is cobalt different from standard HSS?
Cobalt (M35, 5%) withstands higher heat and stays sharper longer, making it ideal for harder metals compared to standard high-speed steel.
Do I need cutting paste when drilling metal?
We recommend TTP CUT-IT cutting paste for smoother drilling, cooler operation, and longer tool life.
What customers say
Average rating:
4.9 / 5 ·
Based on
154 reviews
- DIYMark (YouTube) — “TTP HARD outperformed leading US bits on tough metals.”
- Catus Maximus (YouTube) — “Impressed with the M35 cobalt set and CUT-IT paste.”
- Customer — “Clean holes in stainless; slower RPM + paste made the difference.”
Reviews reflect the TTP HARD cobalt drill bits range. Independently tested and certified for hardness by SGS Testing.
4mm cobalt M35 metal drill bits
Drill stainless steel and harder metals easily:
- Heavy Duty Cobalt Drill Bits
- Suitable for drilling harder metals including stainless steel
- Used by professionals and home improvement enthusiasts
- Can be resharpened
- Rockwell hardness C average of 66 certification
- Money Back Guarantee
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4mm Drill Bit for Metal – Durable, Accurate, and Built to Perform
Cut cleanly through steel, stainless, and aluminum with our 4mm drill bit for metal. M35 cobalt steel, 135° split point, and USA-backed quality.
Engineered for Demanding Metal Drilling
If you're searching for a 4mm drill bit for metal that won’t let you down when drilling tough materials, look no further. Built from premium M35 cobalt steel, this bit offers excellent performance in hardened and abrasive metals. Whether you're working in a workshop, on-site, or at home, this bit delivers precise results time after time.
Unlike softer HSS bits, cobalt bits stay sharp longer and are far less likely to overheat. The 135° split point design ensures quick penetration without the need for a pilot hole. It also minimizes walking, which is especially helpful when starting holes on curved or uneven surfaces.
Ideal for a Range of Metals
You can confidently use this 4mm cobalt drill bit on a wide variety of metals, including:
Stainless steel (including 304 and 316 grades)
Mild and hardened steels
Cast iron and carbon steel
Brass, bronze, and copper
Aluminum and alloy metals
To increase lifespan and improve drilling efficiency, we recommend using TTP CUT-IT metal cutting paste—perfect for reducing friction and heat during drilling.
Get the Best Drilling Performance
Need to fine-tune your drill speed and feed rate? Use our free Speeds & Feeds Calculator to find the perfect settings for your material and drill bit size. This ensures cleaner holes, reduced wear, and professional results with every job.
Trusted by Metalworkers Across the USA
This 4mm drill bit for metal is a customer favorite. Why? Because it works. Professionals and hobbyists alike rely on it for its balance of toughness, precision, and long life. Check out our Customer Reviews PDF to see what others say after putting it to the test.
We back every drill bit with a full money-back guarantee. If it doesn’t meet your expectations, we’ll make it right.
Summary
The 4mm drill bit for metal offers exceptional cutting performance, durability, and reliability. With its 135° split point and cobalt alloy construction, it's ideal for stainless steel, mild steel, and other tough metals. Combined with cutting paste and the right RPM settings, this bit will help you tackle demanding jobs with ease.
Additional information
| Weight | 0.2 lbs |
|---|
Prices : All Prices are United States (US) Dollar ($) Shipping : We ship from Michigan Warehouse across North America & Canada (Max cart weight 4.2lbs for Canada)