Sword Construction and Blade Geometry

Some older threads compiled. Something a little different

Many of you have subscribed to this Substack because of my articles looking at the historical origins for King Arthur. This has generally been my focus on here for the last few months especially, but I have also been an amateur blacksmith for some years now, and I occasionally like to write on it here as well. I have a few projects lined up that had to be put on hold for a while for various reasons, and hopefully by the end of the year I will have multiple articles out on multiple Seaxes I have in the pipeline, as well as my long awaited recreation of the Kutuluk Club.

Most European swords that we are all familiar with have a certain amount of broad commonalities in their design and construction, with specialization for different tasks developing as the need arose. Swords were primarily a one handed secondary weapon prior to developments in plate armour, and especially in their early use a major status symbol. Early iron swords were quite expensive items until the high medieval period.

Swords may seem like a simple item, but are deceivingly complex. Even the earliest European swords had complex geometry mimicking earlier cast bronze swords, with ridges and fullers forged into the sword for both strength and weight savings.

If you were to take a long flat bar of iron sharpen it to a point, and give it edges and attach a grip you would have quite a sword like object right? In looks, yes, but in function not quite. There are some key things that make swords usable weapons. We'll start with hilt construction and then move on to rough blade geometry. Below you will see a short video showing the parts of a late Roman spatha I am planning on making eventually.

Hilt Construction

The tang of the sword runs through the guard, grip, pommel, and if present peen block. The tang of the sword is then mechanically formed or peened over the pommel or peen block solidly affixing the handle assemble to the sword itself. Glue is sometimes used as well.

So you have a grip affixed to your sharpened bar of iron, Is it a usable sword yet? Closer, but it will still be very tip heavy. Contrary to popular belief you can't just make a sword feel better in the hand by adding more mass to the grip in the form of an oversized pommel. This is where the complex dimensions come into play. Swords need to taper. You might look at a picture of an migration era sword like the one below and think that doesn't look tapered at all, but in fact it is, just not in the direction you think.

Most western swords are tapered significantly distally, meaning that the thickness of the blade near the hilt may be a massive 7-9mm thick, while towards the tip it will taper down to as little as 2-3mm! This can be seen in the pictures below. Tapering ~6mm to 2mm.

This is what makes the difference between a 2.5lb one-handed sword that feels sluggish, and a 2.5lb one-handed sword that feels nimble. Without the taper you could add weight and get the same balance point but the sword without proper taper will still feel much worse in the hand, and ultimately will suffer in performance across the board. From here on you have your many choices to make, is it going to be a chopper? Is it meant for thrusting? General use? These questions will help determine how the sword would be constructed, especially in the late medieval period whenever swords were diversifying heavily.

Blade Profiles

Here we will look at some common blade profiles and see how they effect a sword of similar thickness, length, and profile.

Each sword here is roughly 88cm long, 4.5cm wide, and 6mm thick at the tang. This will allow us to see how the weight and center of mass varies between each profile. The weights may seem a bit light but bear in mind there are no grips or pommels on these.

Because of Substack‘s limits on the amount of images you can add I have condensed the examples of each type into the following image. The red cross on each shows the center of mass for each.

1. Hollow Ground. A very unique blade profile, capable of an extremely acute cutting edge, making hollow ground blades extremely sharp, while retaining rigidity by having a very thick central 'spine'. The downside to this is that the edge is relatively unsupported, and easily damaged. The hollow ground version of our blade comes in at 462 grams, with a CoM 35cm from the tip of the tang.

2. Lenticular. By far the most common blade type seen in prior to the late middle ages. Is a balance of rigidity and flexibility, very important when dealing with iron of varying qualities. The edge is very well supported and thus fairly durable. The lenticular version of our blade comes in at 798 Grams, with a CoM 40cm from the tip of the tang

3. Lenticular with Fuller. This profile is the same as the lenticular, but with a fuller. A fuller (colloquially and erroneously known as a 'blood groove') serves one main purpose, to lighten the blade and conserve material, without sacrificing significant amounts of strength. The lenticular with fuller version of our blade comes in at 671 Grams, with a CoM 39cm from the tip of the tang. Note That over 120 grams have been saved with the addition of the fuller, with the CoM barely being affected.

4. Diamond. A diamond profile provides well supported edges and a very still spine, at the cost of increased weight over hollow ground, but with a more acute cutting angle than lenticular. Diamond is a middle ground jack of all trades master of none kind of blade profile. The diamond version of our blade comes in at 600 Grams, with a CoM 38cm from the tip of the tang.

5. Diamond with Fuller. Much the same as the Lenticular with fuller, the main purpose is to decrease weight. In this instance the fuller will actually make the blade a better cutter as it reduced the resistance inherent to the diamond profile. The diamond version of our blade comes in at 560 grams, with a CoM 41cm from the tip of the tang.

6. Hexagonal. Hexagonal is by far the stiffest profile we are addressing here, and it comes at a cost, increased weight, and decreased cutting ability. The edge is extremely well supported however, and can take much abuse. Many cheap wallhangers these days will sport this profile. The hexagonal version of our blade comes in at massive 1082 grams, with a CoM 39cm from the tip of the tang.

These are not the only variations on blade profile, and I may as I feel compelled add more. Sometime multiple fullers are used etc, sometimes there is slightly more complex geometry involved combining multiple profiles.

There is much more to think of when designing a sword at the end of the day, but these I feel are important points that can help folks who aren’t necessarily interesting in designing and making their own understand some design elements, and maybe some things to look out for if one is buying off the shelf swords.