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Madness

Eighteenth Century Minting Technology & Techniques

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I'd like to learn more about the way in which coins were manufactured in eighteenth century Great Britain prior to Boulton's Soho Mint.  My area of interest extends from design to distribution and every step in between.  The following would be particularly useful:

  • Suggestions of resources from credible sources, either printed or online
  • Images of equipment used in their production, such as dies/punches/matrices/collars etc
  • Your personal knowledge (with attribution if possible)

Thank you!

 

Edit:

My interest was piqued by these two articles:

The 1787 Shilling - A Transition in Minting Technique

The Striking of Proof and Pattern Coins in the Eighteenth Century

 

Edited by Madness

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Coins 728x90

The British Numismatic Journal would be your place to start. A few years ago, someone here put a link up to their entire online resource / archive including index ("of sorts") - hopefully someone will remember and point you to the right place.

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2 minutes ago, Peckris 2 said:

The British Numismatic Journal would be your place to start. A few years ago, someone here put a link up to their entire online resource / archive including index ("of sorts") - hopefully someone will remember and point you to the right place.

Thanks.  Have been reading their journal over the past couple of weeks and edited my first post to show two relevant articles I enjoyed.  Hoped that someone could suggest other sources.  

Edited by Madness

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I previously linked this BNJ article by Dyer & Gasper concerning late eighteenth century minting processes.  Here are a few points I found interesting:

1. They attempt to determine the manufacturing techniques by examining the coins, dies, punches and matrices.  This suggests that there are no detailed contemporary accounts of same.  I imagine the Tower Mint wanted to keep things close to their chests!

2. Proofs and patterns were minted using a collar whereas circulation coins were not

3. The square letter bases we see on proofs of the time result from the use of collars.  The bifurcation we see on letter and number fonts is a result of the manufacturing technique, not the use of a different font.  Because no collar was used to restrict the outflow of the metal, it oozed out the bottom of the letters on the dies thus producing the fishtails.  They claim to have experimentally verified this.

Point 3 seems very odd to me.  Maybe I'm misunderstanding what they say.  Does anyone have anything to add to this?

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Point 3 is perfectly logical. If for example you start out with a blank of whatever dimensions and strike a coin using a flypress without collar, then any pressure applied to the faces which imparts the design will cause the thickness to reduce and the diameter to increase. Just like putting a penny on a railway track and letting a train run over it. If the diameter didn't increase, all the metal flow would have to be into the dies to impress the design onto the blank or to increase the density of the metal (which is never going to happen with the limited forces at your disposal, as it would require a complete breakdown of the metal's crystal lattice structure). As the blank is unrestrained, the metal therefore flows out the sides (as well as impressing the design). 

It is this lateral movement from the increasing diameter that imparts the fishtails.

If a collar is used, this restricts any increase in diameter from lateral flow and so any metal flow must be vertical. i.e. it fills the design features on the dies. You have to have metal flow to make a coin.

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I follow their argument.  However, I've noticed late eighteenth-century coins with a mixture of bifurcated and non-bifurcated verticals in legend-lettering on a single side.  What would cause this?  Uneven pressure during the strike? 

Edited by Madness

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On 8/4/2018 at 10:59 AM, Peckris 2 said:

The British Numismatic Journal would be your place to start. A few years ago, someone here put a link up to their entire online resource / archive including index ("of sorts") - hopefully someone will remember and point you to the right place.

I remember it well, Peck. Can't locate the thread, but have found the link to the BNJ archive resource - it's the same link. I distinctly remember the page layout. 

Can be seen here

 Hope you find it useful @Madness

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Thanks @1949threepence.

I've started my own catalogue here of BNJ that is searchable by author, title and subject with a direct link to the relevant article.  Started at 2014, but have only gone as far back as 2007 so far.

Edited by Madness
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37 minutes ago, Madness said:

I follow their argument.  However, I've noticed late eighteenth-century coins with a mixture of bifurcated and non-bifurcated verticals in legend-lettering on a single side.  What would cause this?  Uneven pressure during the strike? 

Uneven pressure, uneven annealing, variable flan thickness, the 'cleanliness' of the die sinker's work. If you have a variable, it can always conceivably cause a different effect.

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The relative consistency of the fishtailing is remarkable then.

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@Rob It seems as though you know a lot about this topic.  Could you please point me in the direction of some non-BNJ resources that would help me learn about eighteenth-century minting tools and techniques?

Thanks!

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What would cause the two strange lines on the letters below?

Y2IMTab.jpg   NTjJRMK.jpg

Edited by Madness

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The art and craft of coin making - A History of minting technology by Denis R Cooper published by Spinks 1988 ISBN 0907 605 27 3. second hand cost around £250

There are links in Googlebooks and openlibrary, not sure if they show the whole book or parts

 

 

 

 

 

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1 minute ago, Chingford said:

The art and craft of coin making - A History of minting technology by Denis R Cooper published by Spinks 1988 ISBN 0907 605 27 3. second hand cost around £250

There are links in Googlebooks and openlibrary, not sure if they show the whole book or parts

 

 

 

 

 

Crap.  That's an expensive book.  Can someone summarise it please in 200 words or less?  ;) 

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1 hour ago, 1949threepence said:

I remember it well, Peck. Can't locate the thread, but have found the link to the BNJ archive resource - it's the same link. I distinctly remember the page layout. 

Can be seen here

 Hope you find it useful @Madness

I have since found the "index" and uploaded it to Dropbox. 

https://www.dropbox.com/s/wf4g1xl056jj3p2/BNJ contents 1-80 (index of sorts).pdf?dl=0

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18 minutes ago, Madness said:

What would be the cause of the two strange lines on the letters below?

Y2IMTab.jpg   NTjJRMK.jpg

The first might be on the punch itself. Letters are frequently composite, e.g A is often made from an inverted V with the crossbar added separately. The first looks as if the bottom arm was entered separately. 

Punches also broke but continued to be used for the remaining detail, so you could potentially see traces of a different letter. The second looks a bit like a D, but the top of the curve looks more like a die flaw.

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That's really useful information, thanks @Rob.  So in relation to the second example you think the following has happened?

1. A letter "D" punch broke

2. Mint staff removed some remaining metal from the "D" punch to transform it into an "I"

3. Subsequently a die was made using this bastardised letter punch

I wonder why just the curve of the "D" remains?  Too sloppy to clean it up properly?

Edited by Madness

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16 minutes ago, Madness said:

That's really useful information, thanks @Rob.  So in relation to the second example you think the following has happened?

1. A letter "D" punch broke

2. Mint staff removed some remaining metal from the "D" punch to transform it into an "I"

3. Subsequently a die was made using this bastardised letter punch

I wonder why just the curve of the "D" remains?  Too sloppy to clean it up properly?

It may or may not be a D, just that the curve hints at it. The size of letter punches dictates that a change to a different letter would be difficult. A punch has to be harder than the die and is more brittle, so removing previous detail could be problematic or it may be that the relief was low enough to be deemed insignificant. It's all speculation.

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This is the chain isn't it: Matrix -> Punch -> Die ?

I guess then that the matrix would need to be the hardest of them all.  Did engravers do the the bulk of their work directly on a matrix?  Eg. Bust of George, but not the lettering?  I assume, then, that they did something to the matrix after the engraving to make it harder.  

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5 hours ago, Peckris 2 said:

I have since found the "index" and uploaded it to Dropbox. 

https://www.dropbox.com/s/wf4g1xl056jj3p2/BNJ contents 1-80 (index of sorts).pdf?dl=0

Good find - although it is actually an embedded object in the link I posted, under Index of BNJ contents 1903-2010 or as a PDF.

 

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Can anyone recommend a work on eighteenth century typography?

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16 hours ago, Rob said:

....

Punches also broke but continued to be used for the remaining detail, so you could potentially see traces of a different letter. The second looks a bit like a D, but the top of the curve looks more like a die flaw.

[in reference to this image:]

NTjJRMK.jpg

 

I've found an image of an older portrait punch to illustrate Rob's speculation.  Has helped me visualise things better.  

wGDAVpR.jpg

 

Source: Royal Mint Museum website

The comments made re its continued use are illuminating.  

Edited by Madness
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I don't think you would get away with continuing to use that one! Letter differences however tend to be more subtle.

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@Rob

Have you followed the link to the Mint Museum website and read their comments? 

"What is particularly interesting about the portrait punch illustrated here is the area of damage to the front of the bust and that the tool was nevertheless still identified in contemporary inventories as serviceable. One explanation is that, with an engraver spending perhaps as much as a month making such a punch, it may have been more practical to complete the portrait by hand on the die by repairing those missing elements of the neck and drapery than to have to start all over again with a new punch."

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3 hours ago, Madness said:

@Rob

Have you followed the link to the Mint Museum website and read their comments? 

"What is particularly interesting about the portrait punch illustrated here is the area of damage to the front of the bust and that the tool was nevertheless still identified in contemporary inventories as serviceable. One explanation is that, with an engraver spending perhaps as much as a month making such a punch, it may have been more practical to complete the portrait by hand on the die by repairing those missing elements of the neck and drapery than to have to start all over again with a new punch."

Having the broken punch in the inventory as serviceable and it actually being used are two separate things. Company inventories frequently have items in stock which are defective, but not written off for whatever reason (usually financial).

It most closely resembles the first crown bust, but the hair is rendered differently to the one illustrated in Spink. The punch looks a little frosted, which means it could be a proof or pattern bust, or it may be a medal punch, both of which would allow a degree of freedom by the artist when engraving the faulty section. Unfortunately the link doesn't indicate the size or denomination to which it could be applied.

This punch has 10 leaves with a possible 11th at the top. Perusing Hocking gives a couple of possibilities. No. 64 is a crown master puncheon (upper part of head broken away), laureate bust to right, resembling Type ii, but the right leaf is quite hidden. The second is a halfcrown, No. 75 which H says is similar to no. 72 - laureate bust to right resembling the type ii crowns, the tie ends are straight; no.74 says similar to no.72 but there is a tip of an eleventh leaf visible above the head; no.75 says similar to last (broken at upper part of head). I have pictures of Hocking 70-75 and can confirm that none of these resemble the bust you displayed, and in any case the break on no.75 cuts across the forehead and laurels. Neither these two nor any others mention a break at the bottom of the bust. I can only assume Hocking didn't know about this one. The hair relative to the drapery clasp would be more in keeping with a crown punch, as smaller denominations tend to have the hair directly above it.

The mint has a number of punches that can't be assigned to anything in particular. The attached is a punch (Hocking 104) that is in the RM's halfcrown punch tray. It has clearly been used, but is not known for any halfcrown. It does mention a resemblance to the Christ's Hospital medal by John Roettier (MI 1.p.558, n.220), but I don't have this, so perhaps someone else can help here.

Maybe a more detailed study of the first and second bust crowns could shed a little light on this - anyone?

img689.jpg

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