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Mathematical View of the New Pound Coin

48 points by CarolineW 9y ago

deleted 9y ago
[deleted]
helthanatos 9y ago
But why not make the whole coin round?
- shakna 9y ago
  Round is far easier to counterfeit, the overcoming of which was the main goal of this new coin. A round coin can be punched. Non-round means yet another custom tool needs to be brought into the process of creating a fake.
- Latty 9y ago
  Different shapes make for easier identification without looking at the coin (good for the blind, people trying to find a coin in a wallet, etc...), and are harder to fake. It is also, apparently, a reference to the shape of the old threepenny bit.
  - Meic 9y ago
    Which is what a pound will be worth post-Brexit.
gjm11 9y ago
Since the page is inaccessible right now, here's the tl;dr (though it's not long at all): The UK's new £1 coin has 12 sides. That makes it impossible for it to be (like the 7-sided 50p and 20p coins) a shape of constant diameter, which might make it roll less well and make things harder for the makers of vending machines. When OP heard that the new coin was going to be 12-sided, he wrote to the Royal Mint. When the final design came out, it turned out that they'd taken this objection into account but found that a 12-sided coin with curved sides and rounded corners rolls well enough. Very good, but OP would have been happier with an odd number of sides. The end. (Is the constant-diameter property actually relevant to vending machines? It seems to me that unless you're trying to fit the coin down a "tunnel" of absolutely minimal size, what matters is how close it is to constant radius -- i.e., how nearly circular -- and constant diameter is a red herring.)
- Doxin 9y ago
  > Is the constant-diameter property actually relevant to vending machines? It seems to me that unless you're trying to fit the coin down a "tunnel" of absolutely minimal size A lot of cheap coin-op mechanisms put coins through an exactly sized tunnel as first step, so while it's probably not critical, it would be nice to have the coins be constant diameter as now you either need to configure your coin acceptor to be more slack or install a new one altogether.

48 points by CarolineW 9y ago

deleted 9y ago

[deleted]

helthanatos 9y ago

But why not make the whole coin round?

shakna 9y ago
Round is far easier to counterfeit, the overcoming of which was the main goal of this new coin. A round coin can be punched. Non-round means yet another custom tool needs to be brought into the process of creating a fake.
Latty 9y ago
Different shapes make for easier identification without looking at the coin (good for the blind, people trying to find a coin in a wallet, etc...), and are harder to fake. It is also, apparently, a reference to the shape of the old threepenny bit.
- Meic 9y ago
  Which is what a pound will be worth post-Brexit.

gjm11 9y ago

Since the page is inaccessible right now, here's the tl;dr (though it's not long at all): The UK's new £1 coin has 12 sides. That makes it impossible for it to be (like the 7-sided 50p and 20p coins) a shape of constant diameter, which might make it roll less well and make things harder for the makers of vending machines. When OP heard that the new coin was going to be 12-sided, he wrote to the Royal Mint. When the final design came out, it turned out that they'd taken this objection into account but found that a 12-sided coin with curved sides and rounded corners rolls well enough. Very good, but OP would have been happier with an odd number of sides. The end. (Is the constant-diameter property actually relevant to vending machines? It seems to me that unless you're trying to fit the coin down a "tunnel" of absolutely minimal size, what matters is how close it is to constant radius -- i.e., how nearly circular -- and constant diameter is a red herring.)

Doxin 9y ago
> Is the constant-diameter property actually relevant to vending machines? It seems to me that unless you're trying to fit the coin down a "tunnel" of absolutely minimal size A lot of cheap coin-op mechanisms put coins through an exactly sized tunnel as first step, so while it's probably not critical, it would be nice to have the coins be constant diameter as now you either need to configure your coin acceptor to be more slack or install a new one altogether.