How to Sharpen a Sword, Axe or Machete Correctly

A great many swords should not be. Display pieces, stainless wall-hangers and cast-fitting replicas are not built to hold an edge and become far more dangerous than useful when given one. Reenactment and sparring blades are deliberately blunt and must stay so.

Sharpen a sword when it is a genuine hardened working or cutting blade, and when you intend to cut with it. Otherwise leave the edge as it came.

A cutting sword wants a shallow, appleseed convex edge — roughly twenty to twenty-five degrees inclusive, blended into the bevel rather than cut as a crisp secondary facet.

An axe wants twenty-five to thirty degrees inclusive, convex, with the shoulders rounded so it does not stick in the cut.

A machete wants a coarse convex edge, filed, and nothing finer.

None of these want the crisp mirror bevel a pocket knife wants. On a long blade, a fine flat bevel is fragile in exactly the place the impact lands.

Do not draw a long blade across a bench stone; you cannot hold a consistent angle over thirty inches and you will cut yourself reaching. Fix the blade and move the abrasive.

Clamp or brace the sword edge-up on a padded bench, or set the axe head in a vice. Work with a mill file or a coarse diamond plate held in the hand, in short overlapping strokes from ricasso to point, counting equal passes on each side.

Raise a burr along a hand's width, flip, raise it back the other way, then refine with progressively finer stones and finally a strop. The burr is the only honest signal that you have actually reached the apex.

A rolled edge is bent, not lost. Steel it back straight with a smooth rod or the back of a spoon before you remove any metal at all.

A chip must be ground out, and the whole edge around it must be brought down to meet it or the blade develops a wave. Take the chip out over four or five inches, not one.

Never grind a hardened blade on a high-speed powered wheel. The heat destroys the temper silently, and a blade that has lost its temper cannot be given it back at a bench.

Wipe every trace of swarf away, then oil. Carbon steel that has just been sharpened is bare, hungry metal and will bloom rust overnight in a humid room.

Store long steel horizontally or edge-up, never resting on the edge, and never in a sealed leather scabbard for long periods — tanned leather holds acid and will etch an edge in a season.