The Hidden Cost of Replacing vs. Resharpening Drill Bits

There's a default setting in most small shops: when a drill gets dull, throw it in the bin and grab a new one. It feels efficient — no waiting, no logistics, just keep the job moving. The problem is that "just buy a new one" is often 3–5x more expensive than the alternative on a per-hole basis, and most shops have never stopped to verify that assumption.

Let's run the actual numbers.

The Replacement Cost Model

Take a common 1/2" HSS cobalt drill. Quality name-brand (Cleveland, Norseman, Precision Twist) runs $12–$18 new. A shop running medium-duty steel fabrication might get 200–400 holes from a drill before it noticeably dulls. At the conservative end: $15 new, 200 holes = $0.075 per hole in tooling cost.

That's the number shops usually quote when they say drills are "cheap." But there are hidden multipliers most don't count:

• Inventory carrying cost: You need to stock enough new drills that you never run out mid-job. That ties up capital.
• The dull-before-retire effect: Most shops don't throw away drills at first dulling. They run them well past optimal, which degrades hole quality, burns more drill time, increases thrust loads, and occasionally breaks the bit in the work.
• Broken drill recovery: A 1/2" bit broken in a workpiece can cost $50–$200+ in recovery time, scrapped material, or EDM service to extract. The bit was "cheap" — the failure wasn't.

The Resharpening Cost Model

A mail-in resharpening service charges $2.50–$4.00 per 1/2" drill (pricing scales with diameter). Turnaround is typically 2–5 business days. The resharpened drill performs identically to a new drill — same geometry, same cutting characteristics, fresh edge.

A quality HSS cobalt bit can be resharpened 5–8 times before the flute length is too short. Each resharpening restores full performance.

*Import drill estimate reduced for lower tool life from inconsistent grinding and tempering.

The resharpening model wins by roughly 3x on per-hole cost compared to treating name-brand drills as throwaway, and roughly 2x compared to using cheap import drills. These aren't edge cases — they're representative numbers for medium-duty steel work.

The Logistics Objection (and Why It's Solvable)

The most common pushback: "I can't wait a week for my drills." That's a real concern, but it's solved by building a rotating inventory. Send a batch out, keep a backup set running, receive the resharpened set, rotate. Shops doing this successfully typically maintain two full sets of their most-used sizes: one in service, one at the sharpening service or in transit.

The capital tied up in two sets of quality drills is smaller than most shops assume, and it's offset quickly by the per-hole savings.

What Changes When You Sharpen on Schedule

There's a secondary benefit that doesn't show up in pure cost calculations: hole quality consistency. A freshly resharpened drill produces holes within spec — correct diameter, straight walls, good surface finish. A drill run to the edge of failure produces oversize, out-of-round holes with heat-affected walls. In tolerance-critical work, the quality improvement from sharp tooling reduces rework and scrap, which has its own dollar value.

Shops that install a resharpening discipline — pull bits at a defined wear threshold, batch them, send them out, rotate the backup set in — consistently report fewer scrapped parts and less rework from tooling-related failures. The tooling cost savings are the easy-to-calculate part; the quality improvement is often worth as much or more.

The Threshold Question

The one valid reason not to resharpen: bits under about 3/16" in diameter, where resharpening cost approaches replacement cost and the reduced flute length after grinding matters more. For drill diameters below 3/16", replacement is often the right call. For 1/4" and above, resharpening math almost always favors the program.