Yesterday I finished the first arm harness. It works reasonably well as a prototype, although using stainless steel as a prototype material is probably more than a bit questionable. I would use mild steel, but it’s so “squishy” that my thicknesses aren’t right, stainless is at least a decent proxy for the rigidity of carbon steel. Total build time is now on the order of 60 hours, although building a replacement set (now that I have the pattern and techniques) is probably more on the order of a day to a day and a half per arm harness. I also always forget just how much work is involved in grinding and polishing these dang things, since this is easily 2-3 hours per harness.

Some pictures:

The spring pin was an unholy PITA to deal with: I’ll provide a gallery of all the failed pieces for instruction later, but this was the single largest issue with the build, since the vambrace wrapper plate is the single “fiddliest” bit, with 2 rolled edges, a hinge attachment and the pin itself. I had a wrapper fail for BOTH the right AND left arm, so rebuilding these took a lot of time that I wasn’t planning to spend, let alone the proto-prototypes (mild steel) to work out some of the geometry for the vambraces and elbow assembly.

Things that worked well:

• Blending the edges for the vambrace within a millimeter so that the armour looks “right” (one of my pet peeves with “SCA” armour)
• Folding the edges on the vambrace and wrapper BEFORE shaping them (possible because they are a fold, rather than a roll)
• The concept of rolling my excess metal under a rolled edge on the rarebrace
• The general fit of the vambraces, and alignment of the hinges and retaining pins with the rolled edges

Things that did NOT work well

• Welding the retaining stud in the vambrace wrapper
• Construction of the fan (I clearly need practice)
• using the edge of my anvil to flare the fan (which left nicks near the crease in the fan which I couldn’t be bothered to completely clean up for the prototype)
• Elbow articulation geometry (this worked much better when I stopped, threw away the lames and started again with cardstock)
• The shape of the elbow, which is insufficiently pointy. I modelled this (and the central crease) on a Maximillian arm harness from the Churburg collection. Without the gratuitous fluting (which I omitted because it messes up the esthetic) this is a fairly atypical piece – next time I’ll model after one of the Mantova harnesses (or ANY of the earlier Churburg harnesses)
• Creasing the elbow, in a similar fashion to a knee
• Stainless steel hinges (bent without heat – evil metal!)
• insufficient clearance on my rarebrace overlap to fold it into the roll

 
Some pictures of things that worked well (and not so well):

Today I tossed out a pile of elbow lames, because they weren’t quite right. I had spent several hours making these, and they didn’t work properly. The reason that they didn’t work properly is that I had too much “rake” and had put too much curve in them, so that they wouldn’t clear properly.

Half an hour with card stock (really heavy weight paper, about 2/10ths of a mm thick) and I had a new pattern, and a couple of hours later I had the elbows articulating nicely – based on dead flat articulations. I found it useful to articulate these “flat” and then put a (very slight) curve into them once I had them articulating. Here are pictures of the re-patterning, as well as the depth of curvature on the elbow lames.

This led me to question whether I was properly shaping my couters – pics below

I also found that the reshaping eliminated the creases I had put into the lames, and when I re-peaked them I found that I was a couple of millimeters off true for a couple of them. In future I plan to articulate, and THEN put in the medial crease, and I wonder how many armourers articluate after creasing, and how many put in the crease after articulating.

I’ve been cleaning up my heat treated and tempered knees, and thought that it would be useful to make a few notes to remember if you are doing this (or if I’m doing this after a long hiatus, which has been known to happen)

A bunch of this is obvious in retrospect, but my attempt to planish out some surface irregularities on tempered carbon steel was a hilarious (but not at the time) failure. Since I didn’t know how much “depth” I would be losing to firescale I figured that I should do all of my surface updates AFTER heat treating. Oops. This clean-up has taken a whole lot of time, hopefully the rough (150 grit) pass on the other knee will be considerably faster.

So things to remember
Do all of the rough grinding / clean up of surface irregularities before heat treating because:

• Planishing doesn’t work on hardened steel
• abrasives are much less effective on tempered steel
• If I have to clean up any surface irregularities, start with 120 grit instead of 150 grit
• Do all edge bevels before heat treating (when it’s still easy)

More pictures when this gets finished…

I’ve been too busy building things to be doing regular updates, but it’s worth mentioning that I just heat treated a pair of early 15th century articulating knees (Poleyns). The basic treatment is simple enough – heat to between 1500 and 1600 degrees F and quench (I used an oil quench) followed by annealing at 400 degrees for 40 minutes (this was empirically tested). Note that I had a couple of lames (the pieces that articulate) that I had screwed up earlier and / or used to practice technique to test so that I could mess up and / or destroy representative pieces without destroying things I actually cared about!

Part of the concern of heat treating is how much distortion you will get, particularly with hand formed pieces which will have a lot of uneven stresses. To alleviate this we initially heated below the critical range (to around 1200 degrees – still a cheerful orange) and held here for 15 minutes to stress relieve the metal. This did not have a significant impact on the shape (we traced before and after – again, pics below) and eliminating this step did not result in distortion more than a few millimeters (less than 1/16″) on lames. The Poleyns distorted more than this, since we did not have a sufficiently large furnace to play with and had to juggle the quench. This was offset by having very even heat in the furnaces we did use, and a change in our quench technique on the second poleyn led to a much easier quench with less distortion.

Continue reading Heat Treating 15th Century Knee Armour →

Hello

It’s been a while, and a lot has changed in the last year or so. We have moved to Calgary, I’ve started to set up the shop again, and visited the Glenbow museum a couple of times and looked at some nice (and not-so nice) armour.

Hopefully I’ll have time to get some updates up in the next few months, likely starting with 15th century gauntlet construction.

Scott Martin