Historical Sword Heat Treatment
The heat treatment of iron/steel in the medieval period is a very interesting subject. While today we use exact temperature and time control (often in seconds) to get a consistent and repeatable result, the medieval blade maker did this with a material of variable consistency and worked from experience and passed along subjective knowledge. These metal workers of the past had no idea what a degree of temperature was, they read the color of the piece and the fire. They measured time in positions of the sun and church bells ringing, not in fractions of seconds or even minutes of an hour. None of our modern measurement tools and material science knowledge was available to them. Yet the masters of their day where able to use their experience and passed down understanding to create great swords.
They approached the craft as they approached their world. Their attention was on the observable and using what they saw to influence their process. This would often be codified in recipes to imbue attributes into physical objects. They used materials with attributes they wanted to assimilate and processed their objects to impart those characteristics into the piece.
In essence they created recipes for metalworking objects. They had gained a good working knowledge of how the manipulation of time and heat worked to make their iron/steel hard but they understood it from a different perspective than we do today. We use degrees of temperature and timings in minutes and seconds they thought in terms of adding ingredients to the surface of the material or the quench liquid to impart characteristics into the piece.
A great example of this is what comes to us from their own written accounts. The Pol Hausbuch MS 3227a, sometimes referred to as the Döebringer Manuscript, is a fine example of how the medieval mind saw the process. The section just before the discussion of how to use a long sword is about hardening or softening iron/steel. They did not always distinguish between Iron, hard iron, steel and combinations. They looked at it in terms of what the materials intended purpose was.
While to someone unfamiliar to metal working this may seem nonsensical, a blacksmith or blade maker from almost any period would see the value in what these descriptions tell us about practical metal treatment.
Translation from MS 3227a, section just prior to the combat section titled "Of Hardening".
“Now Master Alchemy tells that the first temper is most often in cold water, and this is the common temper. And the temper is recognized thus when the edge is blue – then it is a proper temper.”
– note: cold water is used and the description of the color is what one sees when a blade is quenched and pulled before fully cooling. Often described today as an interrupted quench.
“In clay waters the edges become flexible.”
– note: adding particles to the water or thickening the medium can slow the quench. i.e. a softer result.
“Scythes should be hardened in tallow.” (rendered animal fat)
-note: Tallow has been used as a lubricant and aid in metal working from our earliest records right through to modern industrial steel production.
“Files should be in urine, or in linseed oil, or in buck’s blood.”
-note: The buck should be in heat/rut mentioned later in the Latin verse: “Item anccipe sepum hirinum, cum vritur [virtur] in amore” Also, like all hunting societies – the “Deer-Hunt” was during the rut. This is when the bucks were seen to be the most aggressive and tough. Here we have the ingredients being seen as containing characteristics that they want to have in their end product.
In following posts we will explore MS 3227a in more depth and have a series of topics looking at the way swords, weapons and armor where made in the past.
Translation by Keith Alderson, 2008, unpublished. Additional translations consulted unpublished Matt Galas 2002.