The Shoulder Creep: Why Every Regrind Changes the Blade

Part 4 of a 5-part series on blade geometry and cutting behavior:

1. Sharpness vs. Cutting Ability: Two Things Easily Confused

2. Why Sharpness Fades, But Cutting Ability Doesn't

3. Micro Bevel Instead of a Full Regrind: How to Preserve Cutting Ability

4. The Shoulder Creep: Why Every Regrind Changes the Blade

5. The Recipe for Cutting Ability in CULILUX Knives

   
   

Last time it became clear: eventually, even the micro bevel isn't enough anymore. Its width has hit its limit, its angle is maxed out — now a new full regrind is due. But what actually happens to the blade when that happens?

What Actually Happens During a Full Regrind

Unlike the micro bevel, which only touches the last few tenths of a millimeter at the very tip, a full regrind re-establishes the entire secondary bevel — from the shoulder all the way to the edge. So it's not just the tip that gets renewed; the whole facet responsible for sharpness is ground fresh again.

Why the Shoulder Creeps During This

It's best to carry out the regrind at the same angle as the secondary bevel's original grind. For that angle to hold on a fresh, sharp edge, every regrind has to remove a little material across the whole facet — not just at the tip, but over its full width. The result: the shoulder, the transition from the thick primary bevel to the thin secondary bevel, creeps a small step upward, toward the spine. After a single regrind this is barely noticeable. Over many years and repeated regrinds, though, this creep adds up measurably.

Why This Costs Cutting Ability

And that's exactly where it hits home. Cutting ability isn't determined by how sharp the edge is, but by how quickly the blade gains thickness behind the edge. As the shoulder creeps upward, that point of thickening shifts too — the blade ends up slightly thicker at every point behind the edge than it originally was. The edge itself can still be razor sharp. That's exactly why many knives feel noticeably less cutting-friendly after years of resharpening, even though they've been expertly sharpened again and again.

What You Can Do About It

The technical term for the fix is thinning: not just the secondary bevel is re-established, but the primary bevel itself is ground thinner again, so the shoulder migrates back to its original position and the blade regains its original, slender geometry. This isn't a routine step, though — thinning is already firmly in the territory of the fine art of knife sharpening, and it's usually a job for an experienced sharpener. The good news: depending on the knife and on how it's cared for and sharpened, it can take many years before cutting ability noticeably declines and thinning actually becomes necessary.

What's Coming Next

In the final installment of this series, we'll show how CULILUX knives are sharpened and cared for, so that sharpness and cutting ability stay together for as long as possible.