HSS vs Carbide Drill Bits: Which Should You Actually Buy?

Walk into any Indian tool shop and you'll be offered drill bits in three price tiers that seem random — ₹40 HSS, ₹150 cobalt HSS, ₹2,500 solid carbide. The price spread is real. So is the difference in what they can do. This post maps out which drill bit actually makes sense for your job.

HSS (High Speed Steel)

Standard M2 HSS is the everyman drill bit. Good for mild steel, aluminium, plastics, wood, and brass when run at moderate speeds. A 6 mm M2 jobber drill typically costs ₹30–₹80 and will last for 40–200 holes in mild steel depending on feeds and coolant.

Buy HSS when:

• You're drilling mild steel, aluminium, or plastics at low-to-medium volume
• Hole depth is standard (1D to 5D)
• Machine is a conventional drill press or pillar drill (not high-RPM CNC)
• You can accept that drill life varies with operator technique

Cobalt HSS (M35 / M42)

HSS with 5–8% cobalt added. Retains hardness at higher temperatures, which means it can cut stainless steel, cast iron, and harder materials where M2 burns the edge off in minutes. M35 (5% cobalt) is the common grade; M42 (8% cobalt) is the premium tier.

Buy cobalt when:

• You're drilling stainless steel (304, 316) regularly
• You hit harder materials occasionally (spring steel, hardened cast iron)
• You want one drill that handles mixed-material shops

Cost: typically 3–5× the price of M2 HSS, but you'll get 3–10× the life in stainless or tool steel. Cost-per-hole is better than M2 for any material harder than mild steel.

TiN-coated HSS

Same M2 or M35 body, but with a TiN (titanium nitride) surface coating. The coating reduces friction and increases edge hardness at the very surface. Typical life improvement: 30–100% over uncoated HSS for most materials.

TiN-coated drills are the budget-conscious upgrade — typically 1.5–2× the price of uncoated HSS. If you're already buying M2 jobber drills, TiN-coated is usually worth the bump.

Solid carbide drill bits

Made entirely from tungsten carbide, not steel. 8–10× stiffer than HSS. Runs 3–5× faster feed. Typical life: 500–5,000 holes vs HSS's 40–200. Cost: ₹800–₹5,000 for a single 6 mm drill.

Buy solid carbide when:

• You're running CNC with rigid toolholders, through-coolant, and high RPM
• Hole volume is high (500+ holes per day of similar diameter)
• Tolerance and hole quality matter (carbide runs straighter, less walk)
• Material is hard (HRC 30+, hardened steel, cast iron, titanium)

Do NOT buy solid carbide when:

• You're using a conventional drill press or hand-held drill — carbide is brittle and will shatter with any side-load
• Volume is low (10–50 holes) — cost-per-hole is worse than HSS even at 10× the life
• You don't have through-coolant — carbide run dry or with flood coolant only has a shortened life

Cost-per-hole math

Take 6 mm drilling in mild steel:

• HSS at ₹60, 150 holes = ₹0.40/hole
• TiN-coated HSS at ₹90, 250 holes = ₹0.36/hole
• Cobalt HSS at ₹250, 400 holes = ₹0.63/hole (worse in mild steel — cobalt's strength is harder materials)
• Solid carbide at ₹1,800, 3,000 holes = ₹0.60/hole (worse in mild steel at this volume)

Now same drill in SS304 stainless:

• HSS at ₹60, 15 holes = ₹4.00/hole (burns out fast in stainless)
• Cobalt HSS at ₹250, 100 holes = ₹2.50/hole
• Solid carbide at ₹1,800, 1,200 holes = ₹1.50/hole

The numbers flip based on material. HSS wins in mild steel. Carbide wins in stainless, hardened steel, and high-volume runs.

What most Indian shops actually buy

A common stocking pattern in well-run job shops:

• M2 HSS for volume mild-steel and aluminium work (bought by the 100-piece carton)
• TiN-coated HSS for stainless and mixed jobs (bought by size)
• Cobalt M35 for occasional hardened-material drilling
• Solid carbide reserved for specific production CNC jobs where per-piece time and hole quality justify the price

Brand notes

• Miranda (Indian) — solid M2 and M35 HSS at competitive pricing. Standard stock for most Indian machine shops.
• Ruhi Carbide — Indian solid-carbide drills, jobber and stub series. Good value vs imported carbide.
• Imported HSS — Osborne, Dormer, YG — premium HSS with tighter flute geometry, priced 3–5× Miranda.
• Imported carbide — Sandvik, Kennametal, OSG — production-grade, ₹3,000+ for a 6 mm drill. Justified only for continuous production.

Matching drill to job is the single biggest lever in drilling cost. Tell us the material, hole diameter, depth, and daily volume on WhatsApp and we'll recommend the tier that actually makes sense — not just the most expensive option.

Browse HSS drill bits → | Browse carbide drill bits →