thin planchet 50c

Ozcoins · November 21, 2012, 09:35:06 PM

I was returning some 50c to a coin counting machine, and 1 coin was rejected a couple of times.
I looked a bit closer, and it is noticably thinner than normal.
I weighed it today and it was 13.36g compared to 15.47g for another 50c.
I also measured the thickness using vernier calipers, and it was 2.06mm compared to 2.33mm for the normal coin.

AaronG · November 21, 2012, 10:03:09 PM

So is that actually an error coin? You'd assume so! Nice one, any pics?

Ozcoins · November 21, 2012, 10:09:01 PM

I think so.
I cannot see any way that it got thinner after production.
I'll try to put some pics up.

AaronG · November 21, 2012, 10:13:16 PM

Either can I, nice pick up

enworb · November 21, 2012, 10:19:22 PM

I would expect it is a little weakly struck

purplepennyhunter · November 22, 2012, 07:16:38 AM

Yes, is there weakness present?

Ozcoins · November 22, 2012, 08:17:15 AM

I don't think so. I need to take a closer look, but I think it just looks fairly well circulated.
I think the photo I have on my phone of the coin on the scales is too large to upload, but that looks pretty normal.

AaronG · November 22, 2012, 09:54:52 AM

Is there any way it could have been done by someone on purpose?

Graham · November 22, 2012, 11:21:23 AM

Quote from: 'enworb' pid='3703' dateline='1353498562'I would expect it is a little weakly struck

Why would a weakly struck coin weigh less that a well struck coin? They don't loss weight in the minting process do they? Or am I missing something?

Ozcoins · November 22, 2012, 11:55:05 AM

I think the idea is that the press stops at a certain point, so would not put as much pressure on a thinner blank?
Does anyone confirm if that is actually how it works?

Quote from: 'AaronG' pid='3718' dateline='1353540292'Is there any way it could have been done by someone on purpose?

I have read that acid has been used to make fake thin coins. I think the discussion was about a 2c coin.
If that was done on this one, I think the diameter of the con would have smaller too as all surfaces would be eaten away.
I will measure the diameter and report back.
Does anyone know how acid affects a 50c?

Australian coin · November 22, 2012, 12:14:50 PM

I donâ€™t know?
Then you wouldnâ€™t get a die clash..

Ozcoins · November 22, 2012, 12:30:29 PM

Quote from: 'Australian coin' pid='3730' dateline='1353548690'I donâ€™t know?
Then you wouldnâ€™t get a die clash..

I agree, but I would expect more than just minor marks if the dies hit each other with full force....

Australian coin · November 22, 2012, 12:41:09 PM

Yeah that makes sense, maybe its something to do with area and volume of the planchet.
Ah I have just got a brain strain.

markn · November 22, 2012, 12:49:50 PM

Quote from: 'Ozcoins' pid='3725' dateline='1353547505'I have read that acid has been used to make fake thin coins. I think the discussion was about a 2c coin.
If that was done on this one, I think the diameter of the con would have smaller too as all surfaces would be eaten away.
I will measure the diameter and report back.
Does anyone know how acid affects a 50c?

An acid damaged coin is pretty easy to pick. They have an orange-peely type surface.

Ozcoins · November 22, 2012, 12:57:29 PM

I don't think it was acid then.