Traditional Armor Finishing Processes

[Kristoffer]

Found out that metal scraping is an actual thing outside the japanese swordsmith world.

This is a bit interesting:

https://youtu.be/4FS2YI3U_cc

Also a surface scraping video from 1940.

https://youtu.be/k4lUmE945js


Regarding the.guys with the sticks, I notice that they strap the armour to their benches and the tool is two handed. There is probably quite some force being applied when using the sticks.

[Mac]

Found out that metal scraping is an actual thing outside the japanese swordsmith world.

This is a bit interesting:

https://youtu.be/4FS2YI3U_cc

Also a surface scraping video from 1940.

https://youtu.be/k4lUmE945js

Precision scraping for machine tools is a whole world unto its self.

Regarding the.guys with the sticks, I notice that they strap the armour to their benches and the tool is two handed. There is probably quite some force being applied when using the sticks.

Yes. It looks like they are really bearing down on the tools. I wish our artists had been more observant about the details of securing the work.

Mac

[Cet]

It's going to be very hard to do what I'm supposed to do tomorow and not pull the band of copper I saved from a flywheel and attatch it to a stick.

[Mac]

Is this band of copper suitable to make a "tire" for a wheel? If so.. how big? My wood lathe will only go to just under 12", but I have a left hand thread plate that will let us turn on the unrestricted side of the headstock.

Mac

[Cet]

"Is this band of copper suitable to make a "tire" for a wheel? If so.. how big? My wood lathe will only go to just under 12", but I have a left hand thread plate that will let us turn on the unrestricted side of the headstock. "

That's exactly what it was- about 18" dia if memory serves ( it was part of an ellliptical machine) Not sure how kind I was removing it from the cast iron wheel as i was thinking of it as scrap at the time. thickness is maybe .1" or so.

[Mac]

Golly! An 18" iron wheel with a copper tire. That sounds like the sort of thing that can be made into a lap wheel with a minimum of fuss. You say this came out of an elliptical trainer machine? Do you think they all have them? This is very exciting!

Mac

[Signo]

Is there no risk that copper particles pollute steel surface causing oxidation?

[Mac]

That's an interesting question in light of the trouble I had with copper contamination in my tumbler. viewtopic.php?f=1&t=169445&hilit=mac+bu ... start=1505

I don't think it's likely to be an issue here, since the surface will be subjected to further finishing processes which (presumably) don't involve copper. So, any copper that might get deposited on the surface will almost certainly be removed before there can be any sort of electrolytic trouble.

Mac

[James Arlen Gillaspie]

About a half hour in the Japanese two handed steel 'plane' appears. This video is, for my money, the best of the one hour 'making of the Japanese sword' videos. I keep thinking I ought to make such a plane.

https://www.youtube.com/watch?v=gxwWf-MfZVk

[Thomas Powers]

Technical term for the japanese tool is a "sen"

May I commend to your attention "Lost Country Life" Dorthy Hartley, pages 178-180
which mentions "A deep jar containing grease, and a small bag of sharp sand were taken to the fields for sharpening tools."
and
"Wooden Strickles: these varied in size and shape. Dipped in grease, and then in sand they were used as a whetstone to put a good edge on a scythe or sickle."

[Jason Grimes]

Technical term for the japanese tool is a "sen"

May I commend to your attention "Lost Country Life" Dorthy Hartley, pages 178-180
which mentions "A deep jar containing grease, and a small bag of sharp sand were taken to the fields for sharpening tools."
and
"Wooden Strickles: these varied in size and shape. Dipped in grease, and then in sand they were used as a whetstone to put a good edge on a scythe or sickle."

That's interesting, grease would certainly help with keeping the "sand" on the board longer.

[Signo]

Question : we assume that the tool those polishers use is made of wood. But they all look having some bend due the pressure imparted on the working piece. Could they be instead made of several layers of thick leathers?

[Thomas Powers]

I think the grease helps to keep the abrasive in place until it embeds in the surface of the wood. With emery you could embed it in the surface of soft metals too. I would think that leather would work for final polishes where not much force is needed.

[Jason Grimes]

I think the grease helps to keep the abrasive in place until it embeds in the surface of the wood. With emery you could embed it in the surface of soft metals too. I would think that leather would work for final polishes where not much force is needed.

That makes sense, very much like charging a diamond cutting wheel. In that case, if I'm remembering right, you press diamond dust into a soft cast iron plate and the grains get embedded into the iron. You would want a very hard wood in that case so the grains stay in place?

[Sean M]

Several people cite a "near-mirror polish" on parts of the Madonna della Grazzie armours which were covered by other plates. For example, Toby reproduced photos in the slides for his "An Operator's Guide" lecture, and anything he says about armour is worth taking seriously.

These claims seem to go back to TOMAR p. 265 which cites Mann "The Sanctuary of the Madonna delle Grazzie" Archaeologia 1930. I don't have access, and I think we would want an original copy, not a blurry scan or photocopy (especially if the original is printed on glossy paper). Maybe someone who knows Toby could ask him for the source? I am sure that armourers could 'see' things in the original photos which untrained eyes can't.

A good thread on the finish of the least mucked-around-with bits of original armour is Historical Research -> Original Finish on Armour viewtopic.php?f=4&t=178884&p=2726907 Posts by wcallen and James Arlen Gillaspie here and on the Arms and Armour Forum are good at explaining how armour has been mucked around with in the last 200 years, and why bits under applied fittings or covered by other plates are probably our best chance of seeing something which is not so different from the armour which left the shop. That does not necessarily mean that they were typical, but they are the bits which are least likely to have been roughed up or improved too much.

Jiri Klepac had some comments too back when he was more active online.

[Jason Grimes]

Here is one of the images. It's of the armet when they were conserving it and had removed the brow reinforce and under it was original polish.

period_polish-small.jpg (63.07 KiB) Viewed 1809 times

[Alex Baird]

The only thing about using metal I wonder about would be that wouldn't you want some flex with the boards? I could see that you would have stiff sticks for hard grinding and thinner more flexible ones for fine polishing. The thinner ones would more conform to the surface shape than the thicker ones.

In the illuminations above, it appears some of the sticks are convex and some concave. Perhaps to conform with inner and outer curves?

[Mac]

One of the ways to understand the processes that were used is to look at the marks left by those processed. Looking at the surface which James A G posted a while back, I think I can identify individual scratches which begin and end within the area which was once covered by the rivet.



We can see that the scratches are about the same length as the diameter of the hole. If the hole is the usual 1/8" (3mm), then we can assign a similar length to the scratches. This suggests some things about the tool that made them.

The scratches were probably not made by a hand driven device like a file or a polishing stick. The stroke is too short for that.

If the scratches were made with the periphery of a wheel of some sort, then that wheel probably had a yielding surface. A hard surface (like a grind stone or a lap) would only make tangential contact with the work and the resulting scratches would be quite short. A yielding surface (like wood, felt, or leather) would depress against the work to produce a a longer contact patch and thus longer scratches.

Mac

[Signo]

But, to play devil's advocate, those scratches you indicated could be under the longer scratches that cover most of the surface, and be just leftovers of a previous pass, they show up just because deeper than average.

[Mac]

That may well be. Indeed I suspect that that is exactly the case with the diagonal scratches on the left.

If that is the case, the the scratches may have been produced by a hand driven abrasive, or they may have been made a wheel whose periphery is softer yet.

In addition, it's very difficult to tell if I am really seeing the beginnings and ends of scratches in the picture. One could make better judgements if the object itself were to hand and suitably magnified.

Mac

[Jason Grimes]

The only thing about using metal I wonder about would be that wouldn't you want some flex with the boards? I could see that you would have stiff sticks for hard grinding and thinner more flexible ones for fine polishing. The thinner ones would more conform to the surface shape than the thicker ones.

In the illuminations above, it appears some of the sticks are convex and some concave. Perhaps to conform with inner and outer curves?

That could be a possibility for sure. My only counter to that is if you look at the housebook illustrations you can see that the boards that are not being used are very straight.

It did get me thinking that Mac's idea for using copper (or some other metal) could work. If you attach the metal plate on to the stick with sliding rivets, the board could still flex and the metal should flex with it (if it were thin). The slots wouldn't even need to be very long, just enough to allow the board to flex. The problem with this is that the metal plate would float around as you were polishing. But I don't know how much of a problem it would be, especially if the slots were fairly short?

[Jason Grimes]

That may well be. Indeed I suspect that that is exactly the case with the diagonal scratches on the left.

If that is the case, the the scratches may have been produced by a hand driven abrasive, or they may have been made a wheel whose periphery is softer yet.

In addition, it's very difficult to tell if I am really seeing the beginnings and ends of scratches in the picture. One could make better judgements if the object itself were to hand and suitably magnified.

Mac

This helmet is pretty late is it not? How much hand polishing would have been done at this time? I always sort of assumed that by the late 15th century most armour was polished by some kind of powered wheel (water, animal, or human)?

[Mac]

....I always sort of assumed that by the late 15th century most armour was polished by some kind of powered wheel (water, animal, or human)?

That's my impression as well, but I have to admit that our evidence is pretty slim. We see examples of polishing sticks in the famous hausbuch and in one or two other places, and all of these are 15th C. By the time we get to the 16th C, the hausbuch is showing wheels. At this point, we sort of jump ahead to images by Stradanus and Bruegel where wheels are used.

It's tempting to think that wheels replaced hand work around 1500, but I don't think we have enough evidence to prove that.

To make matters, more complex, we have images of sword grinding/sharpening/polishing(?) happening on what are almost certainly natural stone wheels from at least as early as the 14th C

Mac

[Jason Grimes]

To make matters, more complex, we have images of sword grinding/sharpening/polishing(?) happening on what are almost certainly natural stone wheels from at least as early as the 14th C

Mac

Wasn't there one of a man grinding a knife and two unhappy young men (his sons?) turning the stone with cranks on either side that dates from the 13th C or was that also from the 14th?

There are so many variables to think about on this, maybe what we are seeing is that large equipment like this (wheels of stone or wood) can be very expensive and hard to find room or suitable places to install. As time goes on and the guilds become more organized and have more resources, we see more wheels being used?

[Mac]

To make matters, more complex, we have images of sword grinding/sharpening/polishing(?) happening on what are almost certainly natural stone wheels from at least as early as the 14th C

Mac

Wasn't there one of a man grinding a knife and two unhappy young men (his sons?) turning the stone with cranks on either side that dates from the 13th C or was that also from the 14th?

This one? It's from the early 14th C. Luttrell Psalter, I think.



Also...

From the 9th C. Utrecht Psalter



and the 12 C. Eadwine Psalter.



Mac

[Jason Grimes]

Yes, that's the one.

The Eadwine Psalter looks to be an almost exact copy of the Utrecht Psalter. What the the guy on the bottom doing? Looks like he is fixing scabbards?

[Mac]

He's using one of those scrapers like the Japanese smiths are famous for....



...and so, for that matter is at least one of these guys from the Romance of Alexander Bodleian Library
MS. Bodl. 264



I can't tell if these guys are using scrapers or some sort of polishing sticks.



But, check out the "gizmo" that all four of them are using to keep the tools in contact with the work. Also note, that they all have horn tip cups at their work stations. I suppose they are full of oil.

Mac

[Jason Grimes]

Ok that is cool! So there are two steps being shown, the first is a rough grind on the wheel, then the blades were scraped to smooth out the grind marks? I don't know how well those scrapers would work for armour? With armour's complex surfaces, etc.

Does anyone know how the Japanese polished their armour?

[Kristoffer]

They usually didn't. They painted it with lacquer mostly.

[Mac]

They usually didn't. They painted it with lacquer mostly.

...and when they didn't lacquer it, they they gave it a brown oxide finish. Now, if my memory serves me, we don't see hammer marks under that russet, so they must bring it to a smooth surface before they oxidize it.

Mac

[Sean M]

Sakakibara Kōzan has a detailed description of the forging and especially the laquering from the customer's perspective, so he may say something about the polishing of armour. My only copy is on paper in another country. Really wish they could sort out the copyright issues and reprint the translation of that book ... or some other similar sources from Japan.

These scrapers should appear in inventories somewhere, maybe under a name which we think we understand.

[Cet]

"Sakakibara Kōzan has a detailed description of the forging and especially the laquering from the customer's perspective, so he may say something about the polishing of armour. My only copy is on paper in another country. Really wish they could sort out the copyright issues and reprint the translation of that book ... or some other similar sources from Japan."

He says that prior to lacquering the plates are either rough from the scraping knife ( SENROKU) or from the coarse whetstone are used on the outer surface to remove the hammer marks.

[Jason Grimes]

Having a rough surface would probably allow the lacquer to adhere better, but I agree with Mac that the browned surfaces would need to be smoother. Maybe they used finer and finer whetstones?

[Ernst]

To make matters, more complex, we have images of sword grinding/sharpening/polishing(?) happening on what are almost certainly natural stone wheels from at least as early as the 14th C

Mac

Wasn't there one of a man grinding a knife and two unhappy young men (his sons?) turning the stone with cranks on either side that dates from the 13th C or was that also from the 14th?

There's also the shop monkeys doing the work in the Rothschild Canticles from c.1300, although the edge has been trimmed away.

[Mac]

Having a rough surface would probably allow the lacquer to adhere better, but I agree with Mac that the browned surfaces would need to be smoother. Maybe they used finer and finer whetstones?

The Japanese russet finishes I have seen have a sort of rough texture, which I think they try hard to cultivate. As such, the metal does not need to be mirror like, but only free of hammer marks.

Mac