Vickers Tester

gnome · February 10, 2019, 11:38:23 AM

I came across an interesting article on an American fb page about something called a Vickers Tool and a Vickers die test mark, a small Pyramid shape mark that appears in the fields of coins. "The pyramid shapes were the tip of the Vickers Hardness Tester that were pressed into the die.These test marks appear in Indian coins beginning in the 1930's." This info was borrowed from the site along with some pictures for educational purposes. More than one test mark could be used. This got me thinking about another article I recently read about the restrike proof 1942 Iand 1943 I pennies done in 1965 from India by mail order. There is a small die marker between the I and the back of the head, in the shape of a diamond. Diamond /pyramid shape. The reason wasn't clear for it. The Americans were using a die tester called a Rockwell Tester, a different style of mark. Pics below also borrowed for the purpose. Now this really got me thinking if the Americans and Indians were using these instruments did other mints such as ours and the english mints use them to. Next question to arise was if they did what would some of the coins be. First to come to my thoughts was the 1937 I dot crown, followed by the 1939 bar variety penny, possibly a multi test, the 1941 high dot beside the Y, and maybe the 1945 KG dot. This is just some thoughts as I only have limited access to records. So the question is did the early mints of Melbourne and Sydney use similar testers? Is there a list of workshop tools somewhere that were used at the Sydney and/or Melbourne mints available. Have been asked to share responses on an fb page if that is ok and are any to share. Thanks.

gnome · February 10, 2019, 11:55:20 AM

Borrowed Image of diemarker on the proof 1943 I restrike penny.

gnome · February 10, 2019, 11:58:01 AM

gnome · February 10, 2019, 11:59:47 AM

gnome · February 10, 2019, 12:00:57 PM

Mister T · February 10, 2019, 12:02:06 PM

I think Fred Lever postulated the 1919 and 1920 dots were from such a tool in article in the last few years.

Got a link to the article?

gnome · February 10, 2019, 12:03:19 PM

gnome · February 10, 2019, 12:06:14 PM

The Vickers Tester in question used by the Indian mint since the 1930's.

The Rockwell tester used in America. Definition: A Rockwell hardness tester is used to measure the hardness of metals in the U.S. Mint. It measures the depth of penetration of a steel or diamond-tipped pin relative to the applied force.

gnome · February 10, 2019, 12:08:57 PM

Ok thanks Mister T, will track it down

nealeffendi · February 10, 2019, 01:24:13 PM

According to wikipedia the Vickers hardness test was developed in 1921 at Vickers Ltd as an alternative to the Brinell method. So not possible that the dots on the 1919 and 1920 pennies are due to the Vickers test (and Brinell used a 10mm ball of either steel or tungsten carbide so would be too big to make die marks).
The Rockwell hardness tester was patent applied for on 15/7/1914 and the patent approved 11/2/1919. So in theory they could have used a Rockwell tester to create the dots on the 1919 and 1920 pennies, however the commercialization of the tester didn't happen until the 1920s (plus would a branch of the Royal Mint buy equipment from the yanks?).

autocoupler · February 10, 2019, 03:21:49 PM

Interesting thoughts there Gnome. Some of the anomalies almost seem too perfect to be random.

Like this 1922 penny with a perfectly round dot above upstroke of N in PENNY

And as you say, this 1945 big dot after KG

And as you pointed out, the high Y dot, not perfect but does resemble the Vickers test tool somewhat!

gnome · February 10, 2019, 05:13:04 PM

I did read something about a dot etc right in the middle of a die. Have to try and find it again, could take me abit, though.
That looks pretty much dead centre on the 22.

Mister T · February 10, 2019, 05:36:54 PM

Quote from: 'gnome' pid='118448' dateline='1549780984'I did read something about a dot etc right in the middle of a die. Have to try and find it again, could take me abit, though.

Yes I've heard of these so called "centering spots" - someone from another forum "The Centering Spot is a small dot punched in the hub so that the design can be placed accurately"

nealeffendi · February 10, 2019, 10:14:29 PM

I doubt that any dot was ever used on the centre of a die. For one thing you wouldn't be able to see it to centre the hub over the die as you cannot see through either the hub or the die to align the centres. If alignment marks are ever used they would be on the edge of the hubs and dies to for example align the second and third hubbing strikes used to impress new dies (and the failure to do so gives us the doubled legends and double nose queens that we variety collectors so love).

autocoupler · February 11, 2019, 01:13:45 AM

A couple of close ups of the dot above N.

What about a mischievous die room worker who wanted to record his time upon this planet for posterity, with just a light tap of a small round punch? :angel: