Sinyeenglon Cobalt Drill Bits Set – 99Pcs M35 HSS for Hardened Metal & Stainless Steel

Sinyeenglon Cobalt Drill Bits Set is built for demanding metalworking tasks. This 99-piece collection uses a high-hardness cobalt M35 composition and a hardened full grinding process to help you cut faster and keep edges sharp longer, even when drilling through hardened metals and stainless steel. The kit delivers a responsive feel, clean chips, and steady bite from the first hole.

Designed for versatility, these bits excel across a range of metals, including stainless steel, cast iron, zinc alloy, titanium, aluminum, and other hard metals. You’ll notice the balance between aggressive cutting and durability, letting you tackle projects without swapping tools mid-task.

Key benefits

• Hardness and speed: Cobalt M35 material delivers fast cutting and extended bit life compared to standard HSS options.
• Wear resistance: Hardened full grinding increases edge durability and keeps bits sharp under tough material conditions.
• Versatile metals: Suitable for stainless steel, cast iron, zinc alloy, titanium, aluminum, and hard metals.
• Organized storage: A sturdy plastic index case keeps drills securely separated for quick access.
• Clear sizing: The lid bottom clearly marks corresponding sizes for fast selection.

What’s included

• 16x 1/16 in
• 16x 5/64 in
• 15x 3/32 in
• 10x 7/64 in
• 10x 1/8 in
• 8x 9/64 in
• 8x 5/32 in
• 3x 11/64 in
• 3x 3/16 in
• 2x 13/64 in
• 2x 7/32 in
• 2x 1/4 in
• 2x 5/16 in
• 2x 3/8 in

Usage tips

• Keep the drill bit vertical to ensure a clean hole and to minimize wandering.
• Operate at a low-to-moderate speed: 200–1000 rpm depending on the material.
• Apply cutting fluid to stay cool and extend edge life during heavy drilling.

Storage and care

The included hard plastic case protects each bit, helps prevent loss, and makes transport simple and organized.