Best 7/8 Drill Bit for Steel: Top 5 Picks for Metalworking
The following guide helps buyers find the best 7/8 inch drill bits for steel and other metals. This selection targets different work needs, from heavy-duty drilling in stainless steel to versatile bits for mild steel and cast iron. Best for professional fabrication, DIY metalworkers, and machinists seeking durable, high-performance bits.
Summary table of selected products
| Product | Best For | Key Benefit |
|---|---|---|
| Hard wood, mild steel, cast iron | Coated M2 HSS with durable shank; good all-around performance | |
| 7/8 Inch Drill Bit for Metal – M35 TiAlN | Hardened metals | High cobalt content, TiAlN coating for heat resistance |
| 7/8 Inch Drill Bit – HSS 4241 | Thick metal plates | Stable performance with 1/2″ shank; robust in use |
| 7/8 Inch Reduced Shank HSS Black & Gold | General metal drilling | Dual coating for smooth drilling and corrosion resistance |
| 7/8 Inch M35 Cobalt Drill Bit — TiAlN | Stainless & hardened steel | High hardness, excellent wear resistance, 135° point |
ANGELSWORD 7/8″ Reduced Shank Drill Bit
Best for general purpose metalworking and hard woods, this 7/8″ reduced shank bit is built for versatility. It uses M2 cobalt high speed steel and a Gold Titanium plus Black Nitride coating for durability and corrosion resistance. The 1/2″ universal 3-flat shank ensures compatibility with most drill presses and power tools. The bit is especially suitable for drilling through mild steel up to 0.75″ thick, cast iron, copper, aluminum alloys, and sheet metal. For smoother results, operate at a lower rotational speed to minimize burr formation.
Who it’s best for: shop professionals and serious hobbyists who need a single, reliable bit for steel, soft metals, and hardwoods. Limitations: performance can depend on drilling speed and material hardness; avoid high speeds on very hard stainless steels for optimal edge life.
7/8 Inch Drill Bit for Metal – M35 Cobalt Titanium Aluminum Nitrite
Designed for demanding metalworking tasks, this 7/8″ bit combines 5% cobalt with a TiAlN coating for exceptional hardness and oxidation resistance. The bit features a 135-degree split point to resist walking on stiff materials and a 6″ total length with a 3″ working length, plus a 1/2″ shank. Best for stainless steel, hardened steel, and cast iron where edge life and precision are critical. A caution: cobalt grades can be brittle if overheated; using moderate speeds helps preserve the cutting edge.
Who it’s best for: machinists and fabricators drilling hard metals requiring high wear resistance. Limitations: may require proper coolant or lubrication and careful speed selection to avoid chipping on brittle alloys.
7/8 Inch Drill Bit – HSS 4241, Reduced Shank
This HSS 4241 bit targets heavy-duty metal drilling with a 1/2″ shank and a reduced design for secure fitting in standard drill chucks. The bit is described as robust for steel and iron applications, suitable for drilling thick metal plates and industrial components. It is a practical option when you need a straightforward, reliable heavy-duty bit without specialized coatings. Best for: general metal fabrication and repair shops needing strong, dependable performance. Caution: ensure proper lubrication and avoid overheating, which can wear the cutting edge.
7/8 Inch M35 Cobalt Drill Bit with TiAlN
Featuring 5% cobalt (M35), this drill bit achieves high hardness and heat resistance, with a TiAlN coating that improves lubrication and reduces wear. The bit has a 135-degree split point to minimize walking on tough materials and a reduced shank compatible with 1/2″ chucks. It’s especially suitable for stainless steel, hardened steel, and cast iron. This choice is best for precision and longevity in demanding metal drilling tasks.
Best for: professionals working with hard steels and cast iron. Limitations: like all cobalt bits, use with proper feed rates and lubrication to maximize edge life and prevent premature wear.
Buying Guide
What material will you drill?
Different 7/8″ bits are optimized for steel, stainless steel, cast iron, or nonferrous metals. Consider cobalt content, coating, and point geometry to match material hardness and thickness.
How important is shank compatibility?
Most bits in this set use a 1/2″ shank or reduced shank. Ensure your drill chuck or rotary tool accepts the shank size. A 1/2″ shank provides better stability on high-torque machines.
What coating matters for longevity?
TiAlN and gold titanium nitride coatings reduce friction and heat buildup, extending edge life in high-temperature drilling.
Do you need a 135° split point?
Yes for harder metals. The split point improves starting accuracy and reduces walking, especially when drilling stainless steel or hardened steel.
Bit length and rigidity
Longer bits drill deeper but can deflect more. For thick materials, prioritize a robust shank and proper coolant to maintain rigidity during drilling.
Practical setup tips
- Use appropriate drill speed and feed rate to minimize burrs and edge wear.
- Lubricate when drilling metals to reduce heat and prolong bit life.
- Keep a steady hand and ensure proper workpiece clamping to avoid deflection.
Maintenance and storage
Wipe bits after use to remove metal shavings and moisture. Store in a dry environment to prevent corrosion, especially for coated bits.
Summary recommendations
- Best overall versatility: ANGELSWORD 7/8″ Reduced Shank Drill Bit for Hard Wood and Mild Steel.
- Best for hardened metals: 7/8 Inch Drill Bit for Metal – M35 Cobalt with TiAlN.
- Best for heavy-duty steel plates: 7/8 Inch HSS 4241, Reduced Shank.
FAQ
- Q: Are all 7/8″ drill bits the same diameter in shank size?
A: Not always; many use a 1/2″ shank or reduced shank, so verify chuck compatibility. - Q: Can I drill stainless steel with a cobalt bit?
A: Yes, cobalt bits perform well on stainless steel when used with proper speeds and lubrication. - Q: Should I use coolant with these bits?
A: For metal drilling, coolant or cutting oil can reduce heat and extend bit life. - Q: What is a split point and why is it useful?
A: A 135° split point reduces walking and helps start holes more accurately in hard materials. - Q: Is a coated bit more durable than uncoated?
A: Coatings like TiAlN or gold TiAIN reduce friction and heat, improving wear resistance. - Q: How do I decide between M2 HSS and M35 cobalt?
A: M2 HSS is versatile for general steel and nonferrous metals; M35 cobalt offers higher hardness for hardened steels.