The Bevel: One Angle to Grind, Another to Hone

Grind the primary bevel a degree or two below the working angle, quenching often in water and never letting the edge change colour. If the steel turns straw or blue at the edge you have tempered it soft, locally and permanently, and the only cure is to grind past the damaged part. That heat arrives far faster than it feels — the thin edge has almost no mass to absorb it, so it reaches tempering temperature while the body of the blade is still cool enough to hold. Light pressure, keep the tool moving across the wheel, and dip it before it feels hot rather than after. A hollow grind from a round wheel is a help, not a fault: it leaves two contact points that register the angle on the stone.

A honing guide clamps the blade at a set projection and rolls at a fixed angle. Set it once, write the projection on the tool, and every future sharpening reproduces the same bevel exactly. Freehand is faster and entirely possible, but it must be a CONSISTENT angle, not a swept one. The failure mode is rocking: the wrist rises through the stroke, the bevel becomes convex, and the very tip ends up blunter than the angle you think you are holding. The marker test catches this immediately. There is no virtue in freehand for its own sake. Use the guide while you learn what the angle feels like, and you will end up able to do both.

A grinding wheel leaves a HOLLOW bevel, a flat stone leaves a FLAT one, and stropping or sharpening on a soft backing leaves a CONVEX one. All three cut; they suit different tools. Hollow is easiest to hone freehand, because the concave face touches the stone at heel and tip and registers the angle for you. Flat is the most stable and what a guide produces. CONVEX — a rounded 'apple seed' bevel — puts the most steel behind the edge and is what an axe or a froe wants, because those are struck and levered. An axe sharpened to a flat 25 degrees will chip on the first knot. That is not a sharpening failure; it is the wrong geometry for a tool that is swung.