I read recently that the alloy used in British bronze coins varied a few times from 1860 to 1971.
Looking at my McDonalds and Renniks though, they both list the same alloy as having been used for halfpennies and pennies from 1911 to 1964. Does anyone know if Australian bronze followed the same alloy changes as British bronze? I imagine that the coins minted in London, Birmingham and maybe India would have used the same alloys at the same time but I haven't seen anything to suggest Australian mints did too.
the currency ACT determined the metal content in Aussie coins
so there weren't changes except for the varying amount of the added alloys
i.e. the tin and zinc that were added to the copper may have had variable content (so I have been told), so you can get a 'tin rich planchet or vice versa for the zinc
Metal composition: 97% copper, 2.5% zinc and 0.5% tin.
Not all the copper was sourced from the one mine either
Yes, looking at the Coinage Act 1909 there's no set fineness for the bronze.
Still, I'm curious as to whether the Australian mints followed the British fineness or did their own thing.
others here might know
Not claiming any knowledge of this, but logic would say that whatever contracts were in place for planchets would have nothing to do with what else a mint was producing. Of course, if a mint was using two dissimilar planchets at the same time, there must surely have been the odd mixup, no?
How about putting a pair of coins through one of those metal analyser gizmos and seeing what numbers pop out? Heck, by now surely the relevant numbers must have been posted somewhere on the net?
Quote from: 'Fulvio' pid='17519' dateline='1370697923'Not claiming any knowledge of this, but logic would say that whatever contracts were in place for planchets would have nothing to do with what else a mint was producing. Of course, if a mint was using two dissimilar planchets at the same time, there must surely have been the odd mixup, no?
I don't understand.
I haven't seen anything written about it for Australian bronze though, and I think one of those composition tests would end up getting expensive due to how many pennies you'd need to do it on (and they're not 100% accurate either).
1965
Schedule—Standard compositions of coins
Sections 13 and 14
Denomination of Coin
Standard Composition
Two hundred dollars......................................
11/12ths gold and 1/12th other metal
One hundred dollars.......................................
11/12ths gold and 1/12th other metal
Fifty dollars.....................................................
11/12ths gold and 1/12th other metal
Twenty‑five dollars........................................
11/12ths gold and 1/12th other metal
Ten dollars.......................................................
92.5% silver and 7.5% other metal
Fifty cents........................................................
Copper and nickel
Twenty cents...................................................
Copper and nickel
Ten cents..........................................................
Copper and nickel
Five cents.........................................................
Copper and nickel
Two cents.........................................................
Copper, tin and zinc
One cent...........................................................
Copper, tin and zinc
Notes to the Currency Act 1965
Note 1
The Currency Act 1965 as shown in this compilation comprises Act No. 95, 1965 amended as indicated in the Tables below.
Repeal
The following Acts are repealed:
Coinage Act 1909;
Coinage Act 1936;
Coinage Act 1947.
an interesting link
http://www.cruzis-coins.com/Grading/MelbourneMint.html
Quote from: 'Mister T' pid='17544' dateline='1370736286'...I think one of those composition tests would end up getting expensive due to how many pennies you'd need to do it on
Sorry, I wasn't overly clear. What I meant was, for a given year where you know the UK coins varied from the norm, take both a UK and OZ penny and test them both. they should be different, but if they're the same, you have your answer.
i don't quite understand now either
the Australian mints made their own penny and halfpennies on site
and to the currency regulations
the bombays and the very early londons and those years are documented and i am fairly certain that the bombays' & calcuttas' were strictly controlled re: dies and metal composition
the London coins esp the halfpennies are very black looking as they made their small sovereign like halfpennies deliberately blackened so they didn't look like a sovvie when all new, coppery and shiney
not sure if it was the metal mix or how they minted them
Because the question was, when they minted our coins, did they use our metal composition, or theirs?
oh ta
thanks
dunno
i'll leave it to you guys :):read:
Quote from: 'Fulvio' pid='17597' dateline='1370786396'Sorry, I wasn't overly clear. What I meant was, for a given year where you know the UK coins varied from the norm, take both a UK and OZ penny and test them both. they should be different, but if they're the same, you have your answer.
Well the thing is I'm not sure if the Australian coins ever used a different alloy or not. I don't think Renniks or McDonald are correct in saying only one alloy was used.
I think it's a valid assumption that the London, Birmingham and Calcutta coins all had the same alloy (what the British were using at the time) but whether Australia kept up with the changes is unclear.
ok
and I reckon Maccas and Rennicks are right
Having done my own research a few years ago, about the Australian Mints and how they were making the coin planchets on site.
ex. variability in the 3% mix - all planchets were made to the 97% + 3%
If you have different information then please post it here as I'd love to know more about it.
over and out
Robbie
According to my source (The Bronze Coinage of Great Britain) British bronze was 95% copper, 4% tin and 1% zinc (but variations could and did occur) until some time in 1923. The Royal Mint would likely have used this alloy for all the Australian bronze they made because why do something else. The Heaton Mint coins may have been different (I think I read somewhere that they intentionally used a slightly different alloy but I can't remember what, why or when). I don't know what would have happened in India or Australia until 1923, or what happened after either for that matter.
The alloy stated by our catalogues apparently didn't come into use in British bronze until 1942 due to a tin shortage (tin came from Malaya which I assume came into Japanese hands) and stopped being used in British bronze in 1945, but apparently it was a good alloy and was used in British coins again from 1959 on.
edit: and to complicate things, apparently both the Heaton Mint and King's Norton Metal Co (another private mint which didn't strike any Australian coins) both used different unspecified alloys and both supplied the Royal Mint with bronze blanks between 1912 and 1919.
Quote from: 'Fulvio' pid='17519' dateline='1370697923'Not claiming any knowledge of this, but logic would say that whatever contracts were in place for planchets would have nothing to do with what else a mint was producing. Of course, if a mint was using two dissimilar planchets at the same time, there must surely have been the odd mixup, no?
How about putting a pair of coins through one of those metal analyser gizmos and seeing what numbers pop out? Heck, by now surely the relevant numbers must have been posted somewhere on the net?
XRF analysis is fairly accurate. But they cost about $30,000.
The mints in the old days didn't put out contracts for blanks. They purchased the copper, zinc and tin; then they made and rolled the bronze themselves and stamped out the blanks.
I've seen some of the old mint record books and they specify the bronze alloy changes with the first taking place in mid 1921 at all mints per instructions from London. The alloy also changed at least twice during the war (WW2) and twice after and then remained constant from the late 1940s.
I'm surprised that Mr Ts reference (The Bronze Coinage of Great Britain) has British bronze changing in 1923, have to wonder why London gave instructions to the branch mints that they themselves were tardy to follow. I was unaware that Heaton and KN supplied blanks to London so that is useful to know.
Quote from: 'nealeffendi' pid='28704' dateline='1379510854'I'm surprised that Mr Ts reference (The Bronze Coinage of Great Britain) has British bronze changing in 1923, have to wonder why London gave instructions to the branch mints that they themselves were tardy to follow.
It does seem odd, though to quote the book "although variations in the alloy occurred [between 1860 and 1923], it was officially set in 1923".