The seax covers a lot of ground, historical examples run from 2 to over 26 inches in blade length. Profiles run from the famous broken back straight edged seax, to bowie-like clip points and long spearpoint fighting blades. I make three primary types of seax right now- a modern EDC styled seax, a larger modern seax, and a traditionally styled spearpoint langseax.
The Modern EDC Seax is a nearly straight cutting edge, with just a light belly near the tip. Generally blade lengths for these are in the 4 to 7 inch range, with 3/32 and 1/8 15N20 or 3/16 8670M. I prefer to do a convex grind, either the partial convexed scandi grind on the thinner blades, or a full convex grind with a reasonable distal taper the thicker models. These are typically paired with a ranger or expedition sheath.
I really tried, when working out this style, to get a clean and simple look to a classic design, while enhancing the all important handle ergonomics. In many ways, the smaller fill a similar place to the wharncliffe, but with a different look and tip usability.
The Large Modern Seax is long handled, with the same overall profile as the EDC modern seax, and generally is going to be done out of 5160 or 8670M with a full convex grind. Blade lengths for this range from 8 to 14 inches. Standard sheaths are often the explorer or ranger sheath models.
With the larger modern style seax, I needed to make some changes to the overall feel and construction of the knife. These are middle sized knives for the type, traditionally being used for heavy butchering, smaller wood chopping, and fighting tasks. Heavy bladed, but still needing to be useful as cutting knives. I run a good distal taper, sometimes a weight relieving 1/3 reverse convex along the spine, and I work the handles longer- both so you have more options to choke fore or choke aft- and also to tune the balance of what is traditonally a fairly blade heavy type of knife.
Lately, some of my "modern seax" style blades have been done in langseax lengths- 16 inches in one case. I hate making piles of divisions, but it might soon be time to specify the "modern langseax" category.
The traditionally styled spearpointed Langseax is - almost- a short sword. With a full convex grind and a single edged spearpoint, these range in blade length from about 10 to 22 inches. I do these with a fairly short, traditional dogbone styled handle and a full tang, though I could do a through tang variation. Again, steel on these is generally going to be 5160 or 8670M with my preference being for a distal tapered 1/4 inch base thickness, full convex grind. This also comes with an explorer sheath.
Large Modern Seax: