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Australian-Coins Forum

Australian Coins, Banknotes and Exonumia => Australian Decimal Circulating Coins => Topic started by: r9453 on June 05, 2013, 06:55:54 PM

Title: 1983 50 cent
Post by: r9453 on June 05, 2013, 06:55:54 PM
I was reading about 'bubbles', MattGold's thread (http://www.australian-coins.net/showthread.php?tid=1027). I googled a bit but didn't find much. Anyway the very same day I found this:

(http://users.tpg.com.au/r9453//1983.50Cent.Obv.jpg)

To me it's like a volcano, raised above the field but with a crater in the centre:

(http://users.tpg.com.au/r9453//1983.50Cent.Obv.Cropped.jpg)

:imnewhere: please explain.

Go NSW Blues :off_topic:
Title: RE: 1983 50 cent
Post by: Fordprefect on June 05, 2013, 07:04:48 PM
I'm seeing Centre Punch prior to drilling a hole. :idea:
Does the reverse show any impact area ?

As to the second part, from NSW but
don't give a toss. :angel:
Title: RE: 1983 50 cent
Post by: robbiegal on June 05, 2013, 07:12:19 PM
thought the footy was on tonight
go the maroons
Title: RE: 1983 50 cent
Post by: r9453 on June 05, 2013, 07:17:58 PM
Quote from: 'Fordprefect' pid='17206' dateline='1370424888'I'm seeing Centre Punch prior to drilling a hole. :idea:
Does the reverse show any impact area ?

As to the second part, from NSW but
don't give a toss. :angel:

Does the reverse show any impact area?
Not really, I can post a pic. I see what you mean by centre punch strike prior to drilling. Why not place it directly at 12 o'clock? :-/

As to the second part, :dodgy:
Title: RE: 1983 50 cent
Post by: Fordprefect on June 05, 2013, 07:33:01 PM
Quote from: 'r9453' pid='17208' dateline='1370425678'
Quote from: 'Fordprefect' pid='17206' dateline='1370424888'

Does the reverse show any impact area?
Not really, I can post a pic. I see what you mean by centre punch strike prior to drilling.
Why not place it directly at 12 o'clock? :-/
Probably did on the next one. :yahoo:

The cupro's are very tough little critter.
I've made up a few 3/8" washers from 20c coins
Hell of whack to get the centre punch right
and tough as hell to drill a hole.
Title: RE: 1983 50 cent
Post by: r9453 on June 05, 2013, 07:43:50 PM
:ok: I get it Ford, I'm used to centre-punching steel before drilling but cupro is a different kettle.

Btw,
Go NSW Blues :off_topic:
:)
Title: RE: 1983 50 cent
Post by: robbiegal on June 05, 2013, 08:02:06 PM
you guys have it sorted by the sounds of things

psssst
go the maroons :drinks:
Title: RE: 1983 50 cent
Post by: JeffH on June 05, 2013, 08:04:45 PM
I've never tried to cut a cupro-nickel coin but know that aluminium and brass clog an angle grinder wheel very quickly. I suspect coins would be similar.
Title: RE: 1983 50 cent
Post by: Fulvio on June 05, 2013, 09:10:59 PM
If it were a strikethrough, the bottom wouldn't be smooth, and there wouldn't be a raised crater around it. So yeah, PMD. But you knew that already. :angel:
Title: RE: 1983 50 cent
Post by: r9453 on June 05, 2013, 10:08:32 PM
"But you knew that already."
Nope, I didn't know  that.
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