The real difference isn’t the metal in the name — it’s where that metal sits. A cobalt drill bit is high-speed steel alloyed with 5–8% cobalt running through the entire bit. A titanium drill bit is ordinary high-speed steel with a thin titanium nitride (TiN) coating on the surface — it is not solid titanium, and that distinction drives almost every practical difference between the two.
Construction: Alloyed All the Way Through vs. a Surface Coating
- Cobalt bits: the cobalt (typically 5% for M35-grade bits, up to 8% for M42-grade) is part of the base alloy, not a coating. Every layer of the bit, from the tip to the shank, has the same cobalt-steel properties.
- Titanium bits: the base metal is standard high-speed steel. A thin titanium nitride layer is applied to the surface, which is what gives these bits their gold color. The steel underneath the coating is no different from an uncoated bit.
This one structural fact explains the rest of the comparison.
Side-by-Side Comparison
| Factor | Cobalt (M35/M42) | Titanium-coated (TiN) |
|---|---|---|
| Construction | Cobalt alloyed through the entire bit | Standard HSS with a thin TiN surface coating |
| Heat resistance | Excellent — holds hardness at high temperatures | Moderate — relies on the coating to reduce friction/heat |
| Best on stainless steel, cast iron, hardened steel | Yes | No — coating wears quickly on hard, abrasive materials |
| Best on wood, plastic, aluminum, mild steel | Works, but overkill for the cost | Yes — designed for this range |
| Can be resharpened without losing performance? | Yes — cobalt properties run through the whole bit | Only partially — grinding the edge removes the coating, leaving plain HSS |
| Typical cost | Higher | Lower |
Which One to Choose
- Choose cobalt if you’re drilling stainless steel, cast iron, hardened steel, or doing high-volume metal drilling where the bit will get hot. The cobalt-through-the-body construction means the cutting edge keeps its heat resistance even after repeated sharpening.
- Choose titanium-coated if you’re working wood, plastic, aluminum, or mild/ordinary steel — general-purpose and occasional household or light-shop use. The coating does its job on softer materials, and the lower price makes sense when you’re not asking it to survive hard, abrasive, or high-heat cutting.
Don’t buy titanium-coated bits expecting cobalt-level performance on hard metals because of the name — the titanium here is a surface treatment on ordinary steel, not a harder base material. If the job is stainless steel or cast iron and the coating wears through partway in, you’re cutting with plain HSS for the rest of the hole.
Related reading: About Titanium: Key Properties, Common Uses, and Where to Buy It — covers raw titanium metal itself (a different subject from the titanium coating on these drill bits).
