What Is HSS Drill Resharpening — And Why Most Shops Don't Do It

Every machine shop goes through drill bits. A box of jobbers gets opened, bits get used, and eventually bits get thrown away when they stop cutting cleanly. It happens so routinely that most shops never question it. But there's a step being skipped — one that can extend the life of every HSS drill by two to five times before it actually needs to be retired.

That step is resharpening. And it's less complicated than most shops assume.

What Resharpening Actually Does

A drill bit cuts with two things: its cutting lips and the geometry surrounding them. When a drill goes dull, it's not that the steel itself wears out — it's that the precise geometry at the cutting edges degrades. The chisel edge widens. The lip relief angle flattens. The cutting lips may become unequal in height. The bit stops cutting and starts rubbing and pushing.

Resharpening restores that geometry. On a proper drill grinding machine, the bit is held at the correct angles while a grinding wheel removes a small amount of material from the cutting faces — enough to expose fresh, sharp steel and restore the original point geometry. The result is a bit that cuts like new, at a fraction of replacement cost.

This is the same process that production machine shops have done for decades. The equipment — drill grinders from manufacturers like WinsloMatic, Darex, and Lisle — exists specifically for this purpose. A quality regrind takes two to three minutes per bit and produces results that are geometrically consistent and repeatable in ways that hand-grinding on a bench grinder can't match.

Why Shops Don't Do It

The short answer is that drill bits got cheap enough that throwing them away felt easier than investing in the process or equipment to sharpen them.

The longer answer involves a few compounding factors:

• Equipment cost. A decent drill grinder runs $300 to $800 for a shop-grade machine. That's a real purchase decision for a small shop, and it's easy to keep deferring it.
• Skill and time. Even with a machine, someone has to learn to use it correctly. A bad regrind produces worse geometry than a worn bit. Many shops tried hand-grinding on a bench grinder, got inconsistent results, and gave up on resharpening entirely.
• Import drill prices. When a 115-piece drill set costs $35, the economics of resharpening look less obvious. The problem is that those cheap imports aren't really saving money — they cut poorly, wear out faster, and create quality issues that cost more in scrap and rework than the drills saved.

None of these are reasons not to resharpen — they're reasons why resharpening got deprioritized in environments where the full cost of running dull tooling wasn't being tracked.

What Gets Restored in a Proper Regrind

A machine regrind on a purpose-built drill grinder restores three critical geometry elements:

Chisel edge. The flat scraping surface at the dead center of the point. A wide, worn chisel edge is the primary cause of excessive thrust and drill walking. The regrind narrows and sharpens it back to specification.

Lip relief angle. The clearance behind each cutting edge that allows the bit to bite rather than rub. Without adequate relief, the bit generates heat rapidly and cuts poorly. Proper relief is restored to the 8–12 degree range standard for most HSS jobber drills.

Lip height equality. Both cutting lips must be at the same height and angle. Unequal lips cause oversized holes — sometimes 0.005" to 0.015" oversize for standard jobber drills. A machine regrind ensures both lips are matched, which is why machine-reground bits hold tighter tolerances than hand-ground bits.

How Many Times Can You Resharpen a Bit

A standard jobber-length HSS drill bit has significant flute depth — enough steel to support multiple regrind cycles before the flute becomes too short to clear chips effectively. For a 1/4" jobber drill, that's typically four to eight regrinds depending on how much material is removed each time. For larger diameters, more cycles are possible.

The practical limit is when the bit gets short enough that chips don't clear the hole before packing. At that point, you retire it. But you'll have gotten the full value out of the steel before that happens.

What MachinistPost Does

MachinistPost is a mail-in drill resharpening service for machine shops and serious hobbyists across the US. You ship your worn HSS drill bits to us; we regrind them on a WinsloMatic — the same type of production drill grinder used in manufacturing environments — and ship them back sharp within the week.

We handle the equipment, the setup, and the consistent geometry. You get sharp drills back without buying a grinder or learning to run one. For shops going through 20 to 200 bits at a time, it's a straightforward cost improvement. For smaller operations, it's a way to get machine-quality results without the capital investment.