Types of Drill Bits: A Procurement Manager's Guide to Choosing Based on Your Actual Job

There's No "Best" Drill Bit—Only the Right One for Your Scenario

I've been buying drill bits for construction and engineering projects for about 11 years now. Managed roughly $180,000 in cumulative spending across hundreds of orders. And I can tell you the single most expensive mistake I see procurement people make: treating "types of drill bits" like a product comparison instead of a job-fit decision.

Here's what I mean. The question "which drill bit should I buy?" is unanswerable without knowing what you're drilling, how often, and what happens if you get it wrong. A diamond tipped core drill that's perfect for a concrete contractor would be a waste of money for a maintenance team doing occasional metal work.

So instead of giving you one answer, I'm going to break this down by scenario. Three common ones. Pick the one that sounds like your operation.

Quick note before we get into it: I'm coming at this from a procurement angle, not a tool-nerd angle. I care about cost per hole, total cost of ownership, and whether the thing shows up when promised. If you want hardness ratings on tungsten carbide, there are better resources out there.

Scenario A: You're Drilling Concrete and Masonry Regularly

This is the heavy-duty end of the spectrum. If your crews are punching through reinforced concrete, block, or brick on most jobs, you're in diamond core drill territory.

A diamond core drill (sometimes called a diamond tipped core drill) uses a hollow cylindrical bit with diamond segments bonded to the cutting edge. The diamond is what does the work—it grinds through concrete rather than chipping it away like a hammer bit would.

What matters most: the quality of the diamond segment and the bond matrix. Cheap diamond core drills use lower-grade diamonds or soft bonds that wear fast. You'll feel like you got a deal upfront, then wonder why you're buying replacements every couple of weeks.

I only believed the "buy cheap, buy twice" line after I approved a batch of low-cost diamond tipped core drills in Q2 2023. We saved about $2,100 on the order. Then we replaced 40% of them within 90 days. Net loss compared to the OEM option: roughly $1,600.

If you're buying diamond core drills, ask your supplier two specific questions:

1. What's the diamond concentration in the segment? (Higher = longer life, higher cost)
2. What's the recommended RPM range for your drill motor?

That second one trips people up. Running a diamond core drill outside its optimal RPM range is the fastest way to destroy it. I've seen crews burn through a $400 bit in a single afternoon because nobody checked the spec sheet against the drill they were using.

On the "1 core drill bit" question: If you only need one size, buy the best one you can afford in that size. One good 4-inch diamond core drill will outperform three cheap ones. Every time.

Scenario B: You're Drilling Metal—Fabrication, Repair, Maintenance

Different beast entirely. Diamond core drills don't do well in metal. You need something with a cutting edge designed for steel, stainless, or aluminum.

Core drill bits for metal typically use high-speed steel (HSS) or carbide tips. The geometry is different—sharper angles, different flute designs to clear chips. If you're drilling large-diameter holes in metal plate or pipe, a metal core drill bit is the right tool.

Here's where I see procurement folks get it wrong: they buy the same brand as their concrete bits and assume it'll work. It won't. Different materials, different tools.

What I look at for metal core bits:

• Coating: Titanium nitride (TiN) or titanium aluminum nitride (TiAlN) coatings extend life significantly in metal. Worth the 15-25% price premium in my experience.
• Shank type: Make sure it matches your drill press or mag drill. Sounds obvious. I've seen three orders get returned last year for this reason alone.
• Cutting depth: Core bits have a maximum depth they can reach. If you're drilling through thick plate, you need the right length or you're wasting time.

Honestly, I'm not sure why some suppliers list metal core drill bits without specifying the material they're designed for. My best guess is it's just lazy catalog management, but it creates real headaches on the procurement side.

Scenario C: Mixed Materials, Smaller Jobs, or "I Just Need Something Reliable"

This is the scenario a lot of smaller contractors and maintenance teams fall into. You're not doing 100 concrete holes a week. You're not running a fabrication shop. You need drills that handle whatever comes up.

The reverse-validation moment: I used to think "multi-purpose" drill bits were a marketing gimmick. Jack of all trades, master of none. Then one of our service crews started using a super rod drill bit for a mix of masonry and light metal work, and I had to rethink that.

A super rod drill bit—if you haven't come across the term—is typically a masonry bit with a reinforced shank and a carbide tip designed to handle intermittent use across harder materials. It's not going to win any speed contests. But it's the tool you grab when you don't know exactly what you'll be drilling.

For this scenario, my advice is different from the other two:

Don't overbuy. You don't need a $500 diamond core drill if you're drilling concrete twice a month. You don't need a full set of metal core bits. Buy a couple of good super rod drill bits in the sizes you use most, and replace them when they dull.

The cost math is simple: if a super rod drill bit costs $45 and lasts 6 months in mixed use, that's $90/year. A diamond core drill might cost $350 and last 3 years in the same role—but only if you're using it correctly, which smaller teams often aren't.

How to Figure Out Which Scenario You're In

This is the part where I stop giving generic advice and you do a little self-assessment. Ask yourself these questions:

1. What percentage of your drilling is concrete/masonry vs. metal vs. mixed?

If more than 70% is one material, buy for that material. If it's spread out, Scenario C applies.

2. How many holes per week are you drilling?

Under 20 holes/week in mixed materials? Go with versatile bits. Over 50 holes/week in one material? Specialize.

3. What's the cost of a failed hole?

If you're drilling anchor holes for structural steel, a failed hole is expensive. Buy the best bit. If you're hanging shelves in a warehouse, the stakes are lower.

4. What's your team's skill level with power tools?

Diamond core drills require more finesse—right RPM, steady feed pressure, water cooling in some cases. If your team isn't used to that, a super rod drill bit is more forgiving.

I don't have hard data on how other companies make this call, but based on our 6 years of order history, teams that match the bit to the primary job type report about 30% fewer replacements. That's not a scientific study—just what I've seen in my own tracking.

One More Thing About Procurement

If you're buying drill bits for a company, get the specs in writing before you order. I can't tell you how many times I've seen a supplier substitute a "comparable" item that wasn't actually comparable.

And check the return policy. Drill bits are consumables in most cases, but defective bits should be returnable. If a supplier won't stand behind their product, that tells you something.

At the end of the day, the best drill bit is the one that gets the job done without wasting your crew's time or your budget. Match it to the scenario, keep an eye on cost per hole, and don't be afraid to switch suppliers if the quality drops.