Vickers Tester

[fred lever]

Hi All.

For Coin and Banknote dot references:
I did quite a few essays on coin dots for CAB, April 2007 on 1953 1/2d, May 2007 on 1946 1/-, Nov 2007 for 1940 to 1948 1d, Nov 11 for 1920 1d.

Neal Effendi and I did a series of articles on the 1920 penny including a large amount on the dots, about 6 in total between sep 2013 and mar 2014.

The clincher on the 1920 dots was my description of the Rockwell type of tester and that was in sep 2015.

I used a couple of forms of "Rockwell" tester in my workshop life, one was a Hydraulic unit, the other you whacked with a hammer! That unit was barely better than using a rounded punch and judging by eye the amount of disturbance to the test piece. The hydraulic unit at least had a gauge that was calibrated in R units, but really it was just a comparator rather than an absolute measure, there were just too many variables.


I never used a Vickers tester, it seems to be a much more sophisticated form of tester and much more accurate so long as the diamond is not damaged.  My  experience was in the much more rough and tumble manufacturing world where testing equipment was more abused and the tip used on the Rockwell could be damaged by the last guy and you could wind up with a groove  rather than a dot. If nothing else read the Sep 2013 article for my observations.

Cheers All, Fred.

[keldaw]

Good info there Fred ,,

[fred lever]

I forgot to mention, Les at TOP END COINS has put a link to the text of the Effendi/Lever articles on the 1920 penny.
Drop into his web site and check out his blog articles, in the Bibliography of his 1919/1920 penny item, he has a link (7) that has a booklet I assembled, "1920 story" or somesuch. Save you ploughing through a bunch of magazines and you can print the lot off in one go.

Fred.

[gnome]

Finally tracked down the images of that centre circle/dot. They were on American coins and the info available is that it is uncertain what they are. A little different to Auto's one, however they are central on the coins, I believe. These aren't my pics, they are from the internet.

[gnome]

[Unicorn]

Great examples Gnome! :good:  AJ would love the Bubbles!

[fred lever]

Hi Auto, may I have your permission to use those 1922 penny pix? I must have another muse about those "centre dots" and draft up a coin article about it all.
Another question, does anybody else have an exactly same  1922?
In other words are we looking at an error on one coin or a die variety that shows on multiple strikings?
Fred.

[gnome]

Thanks Uni,
Sorry Fred, I haven't checked any 22's, but can have a look during the week if that would help.

[autocoupler]

Hi Auto, may I have your permission to use those 1922 penny pix? I must have another muse about those "centre dots" and draft up a coin article about it all.
Another question, does anybody else have an exactly same  1922?
In other words are we looking at an error on one coin or a die variety that shows on multiple strikings?
Fred.

Hi Fred, Feel free to use any image I have posted. Whatever the cause of the central dot on the 1922 penny, one would think there must be others out there?

[fred lever]

Hi Auto, re pix thanks for that.
Yes unless its a one off hit with a cupped punch on the coin (look for a corresponding impact mark on the obverse).
If not that, then it may be a die chip and there must be as you say, others out there
I have a bucket full of 1922, surely I would have seen such a mark already, but I guess i'll have to tip them out on the table and go through them ...urrr...good hunting!
Fred.

[Unicorn]

:laugh2:   know the feeling Fred.

I will go through my 1922's and have a squizz as soon as I can, not a bucket but have a few from memory.

[Basil]

:laugh2:   know the feeling Fred.

I will go through my 1922's and have a squizz as soon as I can, not a bucket but have a few from memory.

I checked mine last night,24 in Total,and no dot.
I have more 1922 Coins in a bag somewhere,check them at a later time.

[Unicorn]

Good on ya Basil! :good:

I tracked most of mine down last night. I think the last time I went through them was with Auto's date work. He's probably closely examined more 1922's than most people. 

From 181 that I could locate, I've found one which I'm sure is it. Will do some pics tonight and post them.

Gee I'd forgotten how good the die clash on some of these are ....... a work for another time.  :winkextra:

[gnome]

Not sure what this is, could be part of the die clash it looks like there is on it.

[autocoupler]

That's interesting gnome, and hadn't noticed it before! Tonight I removed the coin from its saflip to take some more photos, unfortunately, it was before I read your post. By then I had put the coin to bed in a new saflip, but did have another look and took another pic through the holder. Hard to explain, but there is definitely something circular going on low down and just to the left of the E, doesn't jump out at you like it would if there was a surface anomaly, more like it's within the surface lustre if that makes sense.

uni, took some more pics as below, and came up with quite a few die markers that may be of interest to you, the reverse die in particular has had a hard life.

Fred, there is a reasonable close up of the obverse, but can't see anything abnormal that would indicate a cause for the central reverse dot.


   
Depression at lower inner circle and diagonal trench/die crack through date, as well as die crack at foot of second 2.


Could be post mint damage but looks like another trench between IA of AUSTRALIA 


Another pic of gnomes anomaly at bottom of E but pic not as clear as other photo. Also, another trench/die crack at bottom of M in COMMONWEALTH.




Close up of obverse but no obvious sign of something striking through that would cause the dot on reverse.



Elongated cud above E in GEORGIVS.