Concentric Lathe Lines on Predecimal coins.

[gnome61]

Anyone heard or know of any of these. I found this example with a clip.... and a dieclash. 

[gnome61]

[gnome61]

[gnome61]

[gnome61]

Have heard of a couple other examples on a 2 cent and a 50 cent piece, but nothing on the predecimal years.

[autocoupler]

New to me. Looking at the obverse pics I was a bit confused, the I in ELIZABETH is at a denticle, while the I in GRACIA is between denticles. 
Then realised it was a Half Penny, I think.  :blush:

[Basilstate]

I might be on the wrong Tram but weren't the concentric lines ID as Polish marks from the Mint cleaning up Dies with a powered brush?

[gnome61]

This is the information I have read up on them. It's a copy and paste explanation from over the seas.
Lathe rings
Definition: These concentric rings are produced by a lathe which shapes the cone-shaped face of the unfinished working die.  The cone is supposed to be polished smooth before hubbing.  If polishing is omitted or inadequate, the surface will remain covered by concentric lathe marks which will not be erased by subsequent hubbing.

Also borrowed this pic from an American site, purely as a reference .

[Basilstate]

Definition: These concentric rings are produced by a lathe which shapes the cone-shaped face of the unfinished working die.  The cone is supposed to be polished smooth before hubbing.  If polishing is omitted or inadequate, the surface will remain covered by concentric lathe marks which will not be erased by subsequent hubbing.

Ok,i try to stay out of the Hubbing/Die processes but with Oz. coins i was always told if they were raised concentric lines it was from the power brushes the Melb. Mint used to clean up Dies but your explanation sounds feasible.
Fred Lever has researched all this in depth and would know if the Brush theory holds water.

[fred lever]

Thanks Basil, going by memory here, but the one "lathe line" examples I am sure of in Aussie coins are the rims on the Melbourne Centenary Florins.
Some of the dies used press out  incomplete rims, the dies were never finished to a standard that the Mint would normally accept.
You can clearly see lathe tool marks that , I presume, there was no time or inclination to remove.
I did write some articles on how rushed the whole product was, almost in my words a "foreign order" done outside normal shift hours.
The coins were stamped out with dies in "as is" condition never properly finished and only a few "Sample" coins struck.
The rest were all thrown in the bags and put in circulation.
I got into trouble for suggesting that there were never any Proofs, too long ago now for me to remember all the details.
They really were "commemorative tokens", oh, I got into trouble for saying that, as well!!!!

When I get back to coin the world I must look through my collection of coins for concentric or spiral circles.
A lathe tool passing over a piece of stock bar will leave a spiral behind. That comes from having taken a pass across the face of the bar say at fine cutting speed, and then pulling the tool piece back across the face quickly by hand wheel, without moving the tool off the face enough.
A wire brush will leave concentric circles on the face of the hub or die. One is supposed to keep buffing the face of the hub with abrasive mops  to "make the scratches finer". After all that is what Polishing is. There is a whole science in Polishing or Buffing, as to what state the outer layer of the metal is left to achieve various "looks". Any of you guys who have done Telescope lens polishing will know what I mean. I was dumb enough to grind scope lens when I was very young, test them for abberations and get them silvered.
Making coin dies in comparison is Black Smiths work!

Fred.

[gnome61]

Peter Andrews mentioned a while ago there was lathe lines found on a 1966 2 cent piece, (mint was unknown now) and another graded version has turned up on an Australian 50 cent piece. This is the only version I know of so far on the predecimal coins.

[gnome61]

Have just come across this story on them.
https://web.archive.org/web/20200620043637/http://www.errorvariety.com/Lathe-lines/index.html