What size steel for a seax?

The seax is a forging knife — the broken-back profile comes naturally from forging a point down on a straight bar, and the long hidden tang is drawn from the same billet. 1 1/2 × 3/16 in bar makes a 7 in blade with a full flat grind. Historic large seaxes were often thicker than modern reproductions — the Seax of Beagnoth is over 5/16 in at the spine with no distal taper — so 1/4 in is period-correct for a big broken-back; small utility seaxes were thin.

Because there is no ricasso to speak of and the edge is straight, the bar width is set by the tallest point of the blade just before the break, and the calculator's height input should be that dimension.

What a seax was — and what the word actually means

Start with the correction that matters: seax is simply the Old English word for knife. The language compounds it for every kind of blade — a bloodletting lancet, a razor, a pruning knife, a pen knife, a meat knife — so calling something "a seax" says roughly as much as calling it "a knife." The big single-edged blade people mean by the word is one end of a very wide range, and the small utility knife is the norm. Knives turn up in something like half of early Anglo-Saxon burials, in men's, women's and children's graves alike; at York, nearly two thirds of intact blades measure 80–120 mm. These were tools, and some of them were also weapons.

The broken-back profile — level spine breaking at a sharp angle down to the point — is a late and largely English variant, common in the 8th to 10th centuries and roughly a fifth of the Anglo-Scandinavian knives from York. Curved-back is the more common shape across the whole period. The tang runs down the centreline of the blade rather than along the spine, seated in a one-piece wood, horn or bone hilt with no guard and no pommel, and the scabbard is worn horizontally on the belt with the edge upward.

Two more things worth knowing before you sell one as historical. The tidy vocabulary — narrow seax, broad seax, langseax — is 19th and 20th-century archaeologists' labelling, not period usage; "scramasax" appears once, in a 6th-century Latin chronicle, and never in Old English at all. And the Seax of Beagnoth in the British Museum, the famous one with the runic alphabet down the blade, is a spectacular outlier at 72 cm overall and nearly a kilogram, not a typical example. Its runes are botched — out of sequence in places — which suggests the maker was not fluent in them, so the "master rune-smith's signature" reading is invention.

Stock for a seax

Seaxes forge from 7 in of bar into a 12 in knife, which is about as far as a hidden tang stretches without a power hammer. If you have one, a 6 in billet will do.

Widths assume blade height + 1/8 in rounded up to stock; thickness is the finished spine rounded up. Change the inputs above for your own pattern.

Steels that suit it

Questions