Three original spindle whorls

I got these from ebay last year. Now, to have a closer look at them.

Firstly, lead spindle whorls are hard to date, and there is little agreement about when they are from, because in Britain at least, there aren’t any properly dated examples. Instead they are found in the countryside where they have fallen from someone’s spindle.

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Incredible sets of medieval moulds found in France

A few years ago at Mont San-Michel, a lot of stone moulds for pewter casting were found.
Here is the link

http://www.inrap.fr/preventive-archaeology/Events/Virtual-exhibitions/Virtual-exhibitions/Making-Pilgrim-Badges-at-Mont-Saint-Michel/The-site/p-1475-lg1-The-site-and-the-discoveries.htm

They are 14th and 15th century pilgrims badges, often showing St Michael, or the Virgin, or a sword. The detail and artistic skill is wonderful to see, far above my own. 260 fragments were found,

Quote:
“This excavation is exceptional in that it has revealed a workshop for the making of pilgrim badges, the first to have been found in France to date. Exceptionally, the activity is clearly shown by the objects found, the cast-offs, and the archaeological structures, even if the latter are incomplete.
It was not only a workshop for the making of finished objects for pilgrims, but also for the making of moulds for this activity, as indicated by the numerous waste products, rough mould shapes and reworked examples. The whole chain of production was on one site.

However, it is not clear why certain faultless intact moulds were abandoned, especially when it is clear that this type of object was considered to be precious and was transmitted from generation to generation. “

The above indicates a problem similar to that I have mentioned to do with the Coventry moulds, that is, why were they dumped? Many of the Coventry ones are not obviously damaged. What the article doesn’t specify is how faultless the dumped moulds were. It is entirely possible that still usable moulds would have been dumped when fashion changed. Or maybe one part of them broke.

It is interesting though that the moulds were made on the site they were used. What is unclear from the historical records and finds in the UK is whether the pewterer carved his own moulds. I think they may have done so in some occasions, but in others purchased them from stone carvers, but I am not aware of any definite evidence either way. It has been suggested that engravers did the carving, and even that some carved bronze moulds for pewter casting, although none of them have survived. Somewhere more isolated like Mont San Michele would not be conducive to a division of labour, whereas in a town it would be easier to find a good carver.

The website says:
“The quality of the engraving, characterised by great attention to detail, bears witness to the work of craftsmen in full possession of their art, but who were also dependent on the wishes of the monks of the abbey. Written sources inform us that the moulds were the property of the monks and were made at their demand. The monks then entrusted them to metalworkers for the manufacture and sale of the badges, an important part of the profits being paid back to them.”

which still leaves it a bit unclear who the monks had make the moulds and sits oddly with the fact that the casting and the mould making happened in the same workshop.

The photos of moulds that they have made available indicate the usual methods of manufacture, but what is interesting is that they are made of schist and limestone. The limestone is probably from the same source as the Caen limestone, but the schist is not so easily located, perhaps coming from Breton quarries. According to the website the most detailed carving is in the finest grained schist, which makes sense. But oddly the geology book I just consulted says that schist is a moderately metamorphosed rock, made up of very platy minerals, such as mica, which in a schist are large enough to nearly be visible to the naked eye. Which would to my mind make it not very good for carving. If it is so fine grained that it isn’t obviously so wavy and platy, then it isn’t a schist. Certainly some of the Coventry moulds are highly metamorphosed mudstones and the like.

They have the usual holes for locating pins, vents for air etc. One has a clear saw mark in it, proving that they cut the stone up using saws.

Some day I’d like to have a look at these moulds.

Latten maille and the uses of brass in war

And lots of other latten in war gear.

I was browsing through “The medieval inventories of the Tower armouries 1320-1410”, a PhD thesis by Roland Thomas Richardson (Which can be downloaded from the British Library ETHOS service), when I found various mentions of latten. Latten in that period was a copper alloy with mainly zinc and other elements.

Quoting from “Medieval English Industries”, page 82,

“The contract for the mid 15th century effigy of Richard Beauchamp in St Mary’s Church, Warwick, specifies “the best latten”, and analysis has shown this to be a copper-zinc-lead-tin alloy: 84.3% Cu, 9.4% Zn, 2.2% Sn, 1.4% Pb, and the remainder including nickel, iron, antimony, arsenic and silver.”

It is attested as being hard as bronze, and shiny.

Thus one of the uses mentioned by Richardson from the inventories, is to decorate the edge of maille shirts, which you see worn by quite a few re-enactors, the shiny brassiness showing up well against the darker iron or steel. (page 39 of the thesis)

Cap a Pie, who sell maille for re-enactors, sell individual rings for making your shirt or standard look prettier: http://www.capapie.co.uk/index.php?route=product/category&path=59_75

Weirdly though, in the Tower inventories and accounts, there is mention of latten maille shirts! A shirt made completely of latten would not be as strong as iron or steel, so I wonder why. (Pages 41 and 44 of the thesis)

The other use on armour is as a latten border, presumably some sheet riveted onto the iron vambrace (page 78 has a photo)

Latten also crops up as horse armour.

Oddly it is also used, e.g. on page 110, to make fletchings for springald bolts! I presume that they were better able to cope with the stress of use? The other use related to springalds is in 7 nuts of latten, purchased for making 7 springalds. I think the nuts they mean are the ones that hold the long brass rod which is turned to pull back the arms of the springald. Thus they would have been large, strong nuts. (page 111)

Page 167 – There is mention of 10 moulds of latten for casting lead balls for firing from guns. Ten is quite a lot and would enable fairly rapid production, although each mould would surely take a minute or two to cool down when cast into, due to the lead taking a long time to cool.

The title though is a bit of a cheat – what they called brass usually included bronze, the latter word not being around in medieval times. So cannon were made of brass, only they meant the strong 10% tin-copper alloy. There is several mentions of them in the inventories, and usefully, of the people who made them.

Page 166 mentions a small gun of copper purchased from John ‘brazier of Cornhill’ in 1361, and of course by copper they must mean bronze, since only that could take the strain of the gunpowder. Technological terms then were not as definite as they are now, although at other places in the accounts the guns were said to be made of bronze. A brazier was basically a foundryman, someone who cast in bronze or indeed brass, into moulds, whether of stone or clay or suchlike.

The earliest accounts I know of from Scotland of such practise are in the reign of James IV, the 1490’s, when a potter made a mould for casting a gun in. A potter being someone who made metal cauldrons, i.e. pots. There isn’t that much evidence surviving for potters in Scotland, but there must have been some.

So, it is amazing what turns up in peoples research. I urge you all to search through ETHOS to find PhD theses of interest.

A problem you run into when making buckles using stone moulds

I have had the ambition for years now to make good pewter buckles, of the sort in use in the 14-15th centuries for holding shoes shut. Numerous examples can be found in the Museum of London book “Dress accessories” and other books of finds.

The mould I am using is is made of soapstone, which I am using purely because I don’t have access to easily carved limestone or siltstone.

Note that I’m cramming quite a few items into one mould, which was done in the past. Good stone isn’t so cheap and easy to find, and it makes sense to use it for several objects, or use two sides for different objects, as seen in some of the Coventry moulds.

The slight problem is, how do I make sure that both sides have the correct half on them? Dan Towse (http://pbsn3.pbworks.com/w/browse/#view=ViewAllObjects), an experienced SCA caster, reckons they squared the mould sides off and measured. That would work well enough I think; being a cheapskate I don’t always use squared off moulds in order to maximise the amount of stone I can use, yet most moulds I have seen are squared off which certainly strengthens his hypothesis.

So, given the situation I was in, how should I mark either side? I tried using damp red clay in the already carved side, but it did not stick very well and rather marked one side of the stone as you can see at the bottom left:

soapstone buckle moulds in the making

Then I tried pouring wax in, hoping it would stick to the appropriate area. It did, but also spread a little beyond, so it was not as accurate as I would have liked. Still, it was a start.

Next I tried casting metal into it, hoping the white stone would be marked by it. No luck, the white soapstone remained unmarked.

When test casting into the mould though, I found that a partly complete cast could indicate the other side of the mould easily enough:

soapstone mould half done with test casts soapstone mould half done without test casts

So perhaps they did it that way? It would be nice to find some objects that are clearly half made, and that show both sides of the mould. Once you have carved the edge of the area to be carved out, you can carry on carving with the occasional test casting in order to see how you are doing:

I would expect real half-done moulds to show some evidence of this or another way of carving, although if the carver is sufficiently good and artistic they could do it virtually freehand I am sure.

I’m pleased a couple of my castings look like the originals they are based on

All I did was carve the stone mould based on the period design and I made what is probably the same mistake that the original mould maker did, in that neither are quite symmetrical, simple though that is to do when you have a ruler. Maybe he didn’t have a ruler and compass and protractor.  All I used was a ruler to measure the lengths of the sides and width, but didn’t concern myself with getting the angles precisely correct, and unsurprisingly the result was not symmetrical.

Here is a photograph of the belt spangles: Continue reading

The rather important use of lathes by foundrymen

For 7 years now I have been thinking about all aspects of how medieval craftsmen made objects out of bronze or pewter. The method of manufacture of some objects is obvious, from the excavated stone moulds for pewter badges through to the methods of making bells, which are recorded in detail in the 12th and 16th centuries, with nothing much changing in between.

But that still leaves some items unaccounted for. Some, like small bells, are made of sheet metal or else have cores of sand and clay within a stone mould a bit like that for making bullets, but nobody has left instructions for their manufacture.

Others, like mortars and pestles, well, eventually I worked out that they were probably made the same way as bells, and lo and behold, in Biringuccio’s book it says that you make mortars, basins and other vessels which need to be hollow in the middle in the same way as bells (page 268 of the paperback Dover edition).

This means that a founder needs a lathe of sorts in order to turn the core of the mortar.

I did in fact first try to make a mortar by having a wooden pestle and a mortar made, which could then have the earth pressed around them before removing them and sealing it all together, but that proved to be harder to get right than I thought. The pestle I did produce had a lot of flash down one side because the dampl clay was not rigid enough to stay perfectly in shape when I was taking the former out, and the mortar mould has not yet been tried due to the slowness of mould manufacture and drying and issues with melting the metal.

Anyway, what did lathes look like then, of the sort I can use?

Fortunately there are pictures and descriptions, but never enough. Continue reading