Author Topic: New composition for UK 5p and 10p coins  (Read 26168 times)

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Offline tonyclayton

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Re: New composition for UK 5p and 10p coins
« Reply #30 on: January 12, 2011, 12:12:54 AM »
The 5p and 10p coins in my (BU) set are magnetic. Thus Ni-plated steel too, I suppose. :)



Christian

Um - I believe I had just said that.... 8) ;D

Offline <k>

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Re: New composition for UK 5p and 10p coins
« Reply #31 on: January 12, 2011, 12:37:20 AM »
Um - I believe I had just said that.... 8) ;D

No, you said you knew they were nickel-plated steel. Christian noticed his coins were magnetic therefore deduced they were nickel-plated steel too. He took the scientific method of discovery; you just read the label.
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Offline chrisild

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Re: New composition for UK 5p and 10p coins
« Reply #32 on: January 12, 2011, 12:42:02 AM »
Thank you for your continued support. ;) And I did not do anything like measure the thickness; but Tony's post reminded me of the fact that the "old" pieces are not magnetic while the new ones are. So I tried it out too. Will be interesting to see when they actually show up in circulation ...

Christian

Offline andyg

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Re: New composition for UK 5p and 10p coins
« Reply #33 on: January 12, 2011, 12:55:54 AM »


The 2011 is on top...
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Offline chrisild

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Re: New composition for UK 5p and 10p coins
« Reply #34 on: January 12, 2011, 08:59:36 AM »
Ah, thanks for that image. Makes the difference quite obvious ...

Christian

Offline FosseWay

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Re: New composition for UK 5p and 10p coins
« Reply #35 on: January 12, 2011, 09:41:20 AM »


The 2011 is on top...

What date is the non-2011 one? It looks like one of the early ones with rounded edges. The later ones with square edges look thicker, so presumably there isn't such a contrast with the 2011.

Offline andyg

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Re: New composition for UK 5p and 10p coins
« Reply #36 on: January 12, 2011, 08:23:17 PM »
What date is the non-2011 one?

2010 :o



Here we have 2011, 2010 and 1990.
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Offline FosseWay

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Re: New composition for UK 5p and 10p coins
« Reply #37 on: January 12, 2011, 09:01:32 PM »
 :o

Ah, OK. It is a bit of a beast, then!

On a slightly different note, I thought when this change was first announced it was only intended to affect 5p coins, not 10ps. Did I dream this? Or if I'm right, when did the policy change to include 10ps?

Offline andyg

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Re: New composition for UK 5p and 10p coins
« Reply #38 on: January 12, 2011, 09:13:37 PM »
:o

Ah, OK. It is a bit of a beast, then!

On a slightly different note, I thought when this change was first announced it was only intended to affect 5p coins, not 10ps. Did I dream this? Or if I'm right, when did the policy change to include 10ps?

The original notice is attached to the front of this thread, I'm not aware of any other?
The new 10p is the same thickness, btw.

Incidentally I prefer the new size of 5p, much less fiddly than the old.
Of course I've yet to handle a bag full of them though. :)
always willing to trade modern UK coins for modern coins from elsewhere....

Offline tonyclayton

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Re: New composition for UK 5p and 10p coins
« Reply #39 on: January 13, 2011, 11:27:45 PM »
No, you said you knew they were nickel-plated steel. Christian noticed his coins were magnetic therefore deduced they were nickel-plated steel too. He took the scientific method of discovery; you just read the label.

I had not read the label.  I was confirming what my own strong magnet revealed for both sets. ::)

Offline <k>

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Re: New composition for UK 5p and 10p coins
« Reply #40 on: January 14, 2011, 12:30:02 AM »
I had not read the label.  I was confirming what my own strong magnet revealed for both sets. ::)

Ah, but you did not tell us that the first time round. You just wrote:

"I can confirm that in both cases the 5p and 10p are in nickel-plated steel."

It would seem your miraculous magnet can detect metal types as well! Wonderbubble!  ;D
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Offline Figleaf

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Re: New composition for UK 5p and 10p coins
« Reply #41 on: January 14, 2011, 12:52:33 AM »
Am I seeing things or is it just the thickness of the three coins that is different, not the number of reeds?

I like to measure and weigh all my coins. Usually, the diameter is pretty precise, while weights may vary. If so, the only way to vary the weight would be a slightly different thickness.

Peter
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Offline tonyclayton

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Re: New composition for UK 5p and 10p coins
« Reply #42 on: January 14, 2011, 01:11:40 PM »
UK currency laws specify the weight of coins, and banks here weigh coin to check on the value of a bag that is being paid in, rather than using rolls as in the USA. As a result, if a new metal is used then the volume will differ; if the area of the coin is the same then the thickness will increase in the inverse ratio of the densities.

Ignoring the coating, iron (& mild steel) has a density of 7.87 g/cm3. Cupronickel is around 8.9 g/cm3. The ratio of these two is 1.13; in other words the coins will be 13% thicker, a noticeable difference.  The ratio is more or less the same for the 'bronze' coins.

Offline tonyclayton

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Re: New composition for UK 5p and 10p coins
« Reply #43 on: March 31, 2011, 11:01:59 PM »
Except for C, Si and Al, these additions are expensive, therefore unsuitable for coinage. I suspect that mild steel is cheaper than steel steel and hard enough for coinage. Metallurgy and management are prominent, if not decisive to running a competitive mint.

Peter

Mild steel is soft enough to be struck in the coining press.  There is no need to use a stronger carbon steel as the rate of wear remains superior to that of copper based alloys, and a harder metal would result in fracture of the coinage dies.

Offline andyg

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Re: New composition for UK 5p and 10p coins
« Reply #44 on: July 25, 2011, 01:28:24 AM »
Buried in the Royal Mint annual report was this little gem,

Quote
Last year, HM Treasury gave its approval for the 5p and 10p to move to aRMour™ nickel-plated steel. This will now be implemented from January 2012.

full report here
always willing to trade modern UK coins for modern coins from elsewhere....