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secret santa

Missing Waves

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I can't make up my mind whether the pennies with missing waves are truly rare and merit an entry on my Rare Penny site. Example occur for 1934, 1937, 1966 and 1967 (these are the dates that I know about) and I have pictures of fewer than 5 for each date. Although I don't regard them as a truly recordable man-made "variety", they are genuinely collectable and appear to be scarce. At first I created a web page for each year but now I have summarised them on a single page, although I am continuing to update the individual year pages and they can be reinstated at any time if collectors show the interest.

I'd be grateful to know of any other years which exhibit this feature.

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img_1672.jpg

Sorry for the Large picture it was Matts that i bought off him and only had one more ,although  i sold both.Dave groom in the book also mentions other years that i assume he has seen.

 

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Personally I’d just cover them with a generic description page, clearly they are not a true die variety and could presumably occur with any date, especially if a grease-clogged die is the cause as suggested.
 

Jerry

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if I may put forward another possible cause.  If a die is in use and happens to sustain a knock on the top of the die or if die clash is sustained its logical that an engineer would rub the face of the die with something abrasive to try to remove the mark , and a dent on the face would appear in reverse on the coin as a protruding dot or lump .  in the course of rubbing down the face the outer edges of the die would have slightly more metal rubbed away than in the central area  . Now the waves and rocks are only shallowly incused into the die and if the edge of that die were rubbed away then the shallow waves closest to the edge of the coin would disappear completely . the teeth or beads though are cut deeply into the die and would still show strongly on the coin.      Below is a picture of the same coin as Pete's I believe .

1097593073_1921missingwavesPetes.jpg.7f43d7759bb9a106086def61934deb3d.jpg

 

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1880, right hand side with half of the sea and exergual line missing- grease?

 

P1030193.jpeg.e15a0da91326b986cc8e4b8083eff40c.jpeg

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1097593073_1921missingwavesPetes.jpg.7f43d7759bb9a106086def61934deb3d.jpg

Thats a much clearer picture Terry and shows like the 1934 its the rocks that are missing and not just the waves 👍

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29 minutes ago, secret santa said:

Is a picture of the whole reverse available Terry ?

Sorry Richard ,It was Matts [ Nordle 11 ]  picture 29/3/16.   I don't think he posted a full coin picture , 

More Pennies - Page 49 - British Coin Related Discussions & Enquiries - British Coin Forum - Predecimal.com.url

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Hmm I've been thinking- if the 'grease' did fill a die, how come it always seems to fill the die perfectly flat so an area has no detail?

there is no time during a strike for much to happen, and surely some grease will be left on the coin, so it leaves the scene very quickly.

If this is the case, considering the numbers minted, a grease spot would change in volume, and the effect on the coins would be very varied,

 and the coins having a flat blank area would be almost unheard of.....

 

 

And why is it only the sea that gets 'greasy'?????

 

 

P1040755.jpeg.2d14fc8d4d616a78944a9b49fc61eda8.jpeg

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Surely it must be caused by something a bit more robust than grease ? The power with which a die strikes a blank would drive grease out of its way ?

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19 minutes ago, secret santa said:

Surely it must be caused by something a bit more robust than grease ? The power with which a die strikes a blank would drive grease out of its way ?

That depends on whether it can clear the die during the instant the strike takes, which will depend on its viscosity and escape route. I’m sure it usually did clear within a small number of strikes,  exiting on the coins struck and around the collar,  but in the meantime as an incompressible fluid it could have left its mark. I have been using an excavator clearing ditches and putting in drainage and gate posts over the past week, and the forces that can be exerted by pumping a few litres of hydraulic oil around never cease to amaze me. It’s not surprising that a covering of grease could prevent full die contact with flan.
Filled die remains a potential issue to this day, apparently,  if dies have been grease coated for storage. There is a lot on the net. Heritage show some nice examples.

https://blog.ha.com/2019/07/something-is-missing-filled-die-errors/

I have no problem with the appearance of these coins being due to die grease (or indeed other foreign material).

Jerry

 

 

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1 hour ago, secret santa said:

Surely it must be caused by something a bit more robust than grease ? The power with which a die strikes a blank would drive grease out of its way ?

Yes.I was only talking about this the other week to someone about why it occurs.As far as i can find out there is no evidence of grease causing a blocked die in milled coins and just a phrase that has been used over the years.None was really used and was machine oil and i am led to believe the dies were washed after they had been set to strike a certain number of blanks. As you mention the pressure used (which i have forgotten ) if the dies had grease on would be to coincidental IMO to  leave the same parts missing on certain coins .The 1937 proofs ( A reverse ) i think are more likely due to the coin being in Low relief either side of the waves that are central below the lighthouse and again on the two parts on the other side.The other years 1921 & 1934 possibly just down to wear on the die ,although the person i talked to by there own admission was only guessing.

https://www.ebay.co.uk/itm/1937-George-VI-Proof-One-Penny-coin-/133528613684?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=RoK94v15yq838hgYv7cnTr69aSs%3D&orig_cvip=true&nordt=true&rt=nc

https://www.ebay.co.uk/itm/1937-Proof-Great-Britain-George-VI-One-Penny-Freeman-218/154082935889?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2648

https://www.ebay.co.uk/itm/Great-Britain-George-VI-Bronze-1937-1-Penny-NGC-MS63-BN-NICE-BU-KM-845-015/313172444843?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I have looked at a few in hand of which these are some pictures of three i found on the same day.

Edited by PWA 1967

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2 hours ago, PWA 1967 said:

Yes.I was only talking about this the other week to someone about why it occurs.As far as i can find out there is no evidence of grease causing a blocked die in milled coins and just a phrase that has been used over the years.None was really used and was machine oil and i am led to believe the dies were washed after they had been set to strike a certain number of blanks. As you mention the pressure used (which i have forgotten ) if the dies had grease on would be to coincidental IMO to  leave the same parts missing on certain coins .The 1937 proofs i think are more likely due to the coin being in Low relief either side of the waves that are central below the lighthouse and again on the two parts on the other side.The others possibly just down to wear on the die ,although the person i talked to by there own admission was only guessing.

https://www.ebay.co.uk/itm/1937-George-VI-Proof-One-Penny-coin-/133528613684?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=RoK94v15yq838hgYv7cnTr69aSs%3D&orig_cvip=true&nordt=true&rt=nc

https://www.ebay.co.uk/itm/1937-Proof-Great-Britain-George-VI-One-Penny-Freeman-218/154082935889?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2648

https://www.ebay.co.uk/itm/Great-Britain-George-VI-Bronze-1937-1-Penny-NGC-MS63-BN-NICE-BU-KM-845-015/313172444843?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I have looked at a few in hand of which these are some pictures of three i found on the same day.

Nice coins. I presume you bought them , Pete?

Well, if proof dies are affected , then re-working of damaged dies is not the issue here, nor should die wear be as quality control was much more strict than for currency coins. Grease is certainly widely used for rust prevention of ironwork in storage, and probably even more so in the days before central heating and environmental control. But any fluid, even thin machine oil, would prevent a clean strike if trapped between the die/ planchet surfaces. Poor working die manufacture by the strike from the master die/ punch being of inadequate depth might give this appearance though would be surprising for a proof die, and I would have thought the depth of the sea cut into the die would be pretty uniform and thus the presence or absence of waves would be rather ‘all or nothing’. Examples where high points on the coin are affected as shown on the Heritage blog show that die fill did occur, and that fill does not have to be solid, just incompressible as liquids are, including grease. During the strike grease, like the metal of the planchet, will move and it is perhaps not surprising that it gets pushed against the inner rim as the alloy is forced down into the rim recess in the die, cutting off its escape. Grease trapped elsewhere might cause impaired letter strike, reduced high points etc perhaps giving the impression of a worn die.  Can we prove grease as the cause of absent waves beyond doubt? Perhaps not, but affected proofs  likely rule out some of the other possibilities.

Jerry

 

Edited by jelida

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https://www.ebay.co.uk/itm/1934-GEORGE-V-ONE-PENNY-GREAT-BRITISH-COIN-HUNT-/233684905043?nma=true&si=RoK94v15yq838hgYv7cnTr69aSs%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

Yes the 1934 is different from the proof 1937 as its the rocks which are missing and a lot more prominent than the low relief parts of the proof.

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OK, here's another theory. The metal for the creation of a working die has to be annealed, i.e. heated up to soften it to allow the punch to create the incuse image before plunging it into water to harden it. Is it possible that the would-be die might not soften uniformly upon heating and when the punch slams down into the softened metal, the highest points of the punch (which create the lowest part of the die which will in turn create the highest point of the struck coin) comes up against harder (i.e. less soft) metal and does not create as sharper a mould as it should ?

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38 minutes ago, secret santa said:

OK, here's another theory. The metal for the creation of a working die has to be annealed, i.e. heated up to soften it to allow the punch to create the incuse image before plunging it into water to harden it. Is it possible that the would-be die might not soften uniformly upon heating and when the punch slams down into the softened metal, the highest points of the punch (which create the lowest part of the die which will in turn create the highest point of the struck coin) comes up against harder (i.e. less soft) metal and does not create as sharper a mould as it should ?

The evidence from clashed dies tells us that the softening and hardening processes are not a precise art, as clearly one die was harder than the other for it to make an impression. But given the degree of heating required to soften the die, I think you would struggle to get localised differences on the same die. I presume they will put it in an oven/furnace which should give even conditions across all surfaces.

The key to any grease escaping has to be whether it is restrained by a well fitting collar or not. Liquids are virtually incompressible, so at the pressures we are talking about here a sealed unit would have no problem stopping the dies from making contact.

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Hmm, interesting idea, but as the dies were heated in an oven slowly to over 500 C, then cooled slowly before they were worked, I can’t see that an uneven anneal is likely, and the mint workers are very experienced at this sort of thing. The sea/waves on the master die/punch should all be engraved at the same depth and I think it unlikely they could be struck on the slant, which is why I think the sea would either be entirely present, or entirely absent with that scenario, and unlikely absent in part or on both sides of Britannia as is sometimes seen.
I wonder what effect a convex planchet surface would have? Could that be a cause? Unlikely again, as the blanks were punched out of rolled strip. 
 

Jerry

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