Forging Knife Bevels: The Counter-Bend & Banana Fix

Forging bevels stretches the edge while the spine keeps its length, so the blade always curls upward - the fix is forging a deliberate downward counter-bend toward the edge first, so beveling pulls it straight. Technique: tilt the blade 10-12 degrees with a wrist twist, overlapping moderate blows ricasso to tip, both sides evenly, stopping at a dime-thick edge.

Bevels are where forging stops being blacksmithing and starts being bladesmithing — and where every new smith meets the same betrayal: you forge beautiful bevels into a straight blank, and the blade curls upward into a banana. This guide covers the hammer mechanics of clean bevels and the physics (and fix) of the curl, because it isn’t a mistake — it’s geometry, and geometry can be pre-paid.

Diagram: why forging bevels curves a blade upward — the edge stretches while the spine stays put — and the counter-bend fix of pre-curving the blank toward the edge so beveling pulls it straight — The banana isn’t failure — it’s physics. Pre-pay it with a counter-bend.

Why the Banana Happens

Forging a bevel thins the steel toward the edge, and thinned steel has to go somewhere — it flows along the blade, making the edge side longer. The spine, still thick and un-hammered, keeps its length. One side of the blade longer than the other = a curve, always sweeping up toward the spine. More bevel = more curl. Every smith’s first blade does it; experienced smiths just spend the curl before it happens.

The Counter-Bend

Before starting bevels, forge the blank into a downward curve toward the edge — a deliberate reverse banana over the anvil horn or face edge. How much is steel- and bevel-height-dependent; for a typical 3–4″ blade, aim for a visibly wrong-looking droop. As the bevels go in, the stretching edge pulls the curve back out, and the blade arrives straight roughly when the bevels arrive finished. Under-guessed? A little more counter-curve at heat, keep going. It feels like witchcraft exactly once.

Hammer Mechanics for Clean Bevels

Tilt the blade, not the hammer. Rest the blank on the anvil and twist your holding wrist to lift the spine 10–12° — the hammer falls flat while the steel meets it at the bevel angle. Trying to angle the hammer instead produces edge-of-face dents and wandering angles.
Overlapping, moderate blows in passes — ricasso to tip, flip, repeat, keeping both sides even (uneven sides = the blade also curves sideways; the fix is more blows on the shy side, at heat). Think “rows of stitches,” not “big bites.”
Watch the edge thickness constantly. Target is dime-thick (~0.030″) and no thinner — the quench punishes thin edges with cracks and wild warps (see cracked in the quench). Bevels finish at the grinder, not the anvil.
Set the bevel’s start at the ricasso deliberately — a clean plunge-line area is mostly a grinding feature, but a tidy forged transition makes that grind vastly easier.

Corrections at Heat

Banana anyway? At bright heat: light blows along the spine (spreading it lengthens the short side), or bump the blade spine-down against the anvil. Sideways sweep? Even up the bevel work on the shy side. The cardinal rule of every correction: at forging heat only — “just one straightening tap” on a dull-red blade is a crack with extra steps. When forging’s done, head to normalizing, where the stress you just built gets erased before it can bite during heat treat.

Sources

Common Mistakes

Starting bevels on a straight blank (hello, banana). Angling the hammer instead of tilting the blade. Working one side to completion before touching the other. Thinning the edge past dime-thick. Straightening at dull red – that tap is a crack with extra steps.