How Many Times Can You Resharpen an HSS Drill Bit?

The number you'll hear most often is 4 to 6 resharpenings per bit. That's a reasonable ballpark for a standard HSS jobber drill used in mild steel under normal shop conditions. But it's not the limit — it's a starting point for understanding what actually determines when a bit retires.

WHAT SETS THE REAL LIMIT

Every regrind removes material from the point. The cutting edge is rebuilt, but the bit gets shorter. Once the flute length is reduced to roughly 50% of its original length, the bit can't evacuate chips properly in full-depth holes and starts running out of clearance. At that point, the bit is retired regardless of how many times it's been sharpened.

For a 3/8" jobber drill with 3" of flute length, you might get 6 or more resharpenings before hitting that threshold — each grind might remove 1/8" to 3/16" of length depending on condition. For a smaller 1/8" drill that started shorter, you might get 3 or 4 before it's too short to be useful.

SIZE MATTERS

Larger drills get more resharpenings. A 1/2" bit has more total length and more material to work with. A 1/16" bit might only survive 2–3 regrinds before it's too short or too fragile to regrind cleanly. This is one reason large drill inventories cost more to maintain — but also why the economics of resharpening large bits are so favorable. The cost difference between a resharpened 1" drill and a new one is significant.

MATERIAL DRILLED

Stainless steel, Inconel, and abrasive materials like fiberglass wear the cutting edge faster. A bit that would go 5 resharpenings on mild steel might make 3 on 316 stainless before needing attention. The cutting edge degrades faster, and the point may need more material removed per grind to get below the heat-affected or work-hardened zone.

HOW IT WAS USED

A bit run at correct speeds and feeds with proper cutting fluid, pulled and cleared on a reasonable schedule, will outlast one that was pushed hard, run dry, or used past obvious dullness. Overheating — visible as the blue-black discoloration you see on the point — alters the temper of the HSS and reduces hardness. A blue tip tells you the bit has been heat-damaged, and a regrind may restore the geometry but not the full hardness of a properly used bit.

THE PRACTICAL ANSWER

Track your bits if you can — mark the shank with a paint pen dot each time they go in for resharpening. Most shops that do this find bits lasting well past 6 cycles when sized appropriately and drilled in the right materials.

The retirement decision comes from the bit itself: too short, damaged flutes, bent body, chipped lands beyond what a grind can fix. Not from a fixed number of cycles. Send bits when they're dull. Retire them when the physical condition is gone. The number takes care of itself.

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