Setting Up an In-House Resharpening Station: When It Makes Sense (And When It Doesn't)

Every shop that goes through a significant volume of HSS drills eventually considers in-house resharpening. The appeal is obvious: eliminate the per-drill cost of outsourcing, resharpen on-demand, and keep tools in rotation without waiting on shipping. The reality is more nuanced. In-house resharpening done right is genuinely economical. In-house resharpening done wrong wastes more money than it saves and produces drills that perform worse than dull ones.

The Volume Threshold

The first question to answer honestly: how many drills does your shop dull per month? A rough guide:

• Under 20 drills/month: Mail-out resharpening wins. Equipment cost never amortizes.
• 20–80 drills/month: Borderline. Depends on drill sizes and your labor cost per hour.
• 80+ drills/month: In-house typically wins economically, provided you buy the right equipment and assign it to a consistent operator.

These thresholds assume you're sharpening standard jobber-length HSS drills in the 1/8"–1/2" range — the most common resharpen candidates. Specialty geometry (split point, brad point, step drills) requires either specialized fixturing or significantly more operator skill, which shifts the threshold higher.

The Equipment Landscape

There are three tiers of drill sharpening equipment:

Bench Grinder with Drill Grinding Attachment

This is the low-cost entry point and, for most shops, not adequate for precision work. A standard bench grinder runs too fast, generates too much heat at the point, and provides insufficient fixture control for consistent relief angles. Results are highly operator-dependent. Some experienced machinists get good results from a bench grinder, but those same machinists typically acknowledge they're doing it by feel developed over years of practice. A shop that wants consistent, repeatable geometry should not rely on bench grinder resharpening.

Dedicated Drill Grinding Machine (Entry-Level)

Machines like the Drill Doctor series and similar entry-level dedicated grinders produce acceptable geometry for general-purpose shop use. They handle standard jobber drills well, are fast to set up, and require minimal operator skill once dialed in. Their limitations: they don't handle short or long series well, struggle with larger diameters (over 1/2"), and can't produce split point geometry on most models.

For shops in the 20–60 drill/month range that need a quick, reliable result on common sizes, this tier makes sense. Cost: $150–$400.

Precision Point Grinding Machine

This tier includes machines like the Darex E90, Hercules, and similar professional-grade units. These produce consistent split-point geometry, handle a wide size range, and deliver results comparable to new-quality drills when operated correctly. They require more setup time per drill and a more knowledgeable operator, but the output quality is measurably better than lower-tier options.

For high-volume shops, precision drilling operations, or any shop that runs drills through difficult materials, this is the correct tier. Cost: $800–$3,000+ depending on size range and features.

The Operator Factor

Equipment is only half the equation. A precision grinding machine operated by someone unfamiliar with drill geometry produces poor results. In-house resharpening only pencils out economically if the operator can verify results and adjust when geometry is off. Minimum skills needed:

• Ability to read a drill point under magnification — chisel edge, lip height, relief angle
• Understanding of what correct geometry looks like for the materials being drilled
• Ability to set and verify lip angle and relief using a drill point gauge
• Recognition of drills that are too far worn to resharpen economically (usually when the flute depth is compromised)

What In-House Can't Handle Well

Even a good in-house setup has limits. Consider outsourcing these categories:

• Drills with chipped or broken cutting edges that require significant stock removal
• Any drill that requires specialty geometry you can't verify with your tooling
• Very small diameters (under #30 wire gauge) where grinding control is difficult
• High-value specialty drills where a bad resharpen is worse than waiting

The Hybrid Approach

Many shops that crunch the numbers land on a hybrid model: in-house grinding for the high-frequency, standard-size drills (the ones burning through volume), and mail-out resharpening for the precision work, odd sizes, and specialty geometry. This approach captures most of the cost savings without the risk of poor geometry on critical applications.

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