Unusual 1942 3d brass

[barzilla]

Hi, all.

I'm over in the States and I was given a box of coins and such that belonged

to my dad who served in the US Army during WWII.

Amongst these coins was what I first took to be a button, but upon further

examination determined to be a one-sided 1942 threepenny coin.

By one-sided, I mean that the dated side is crisp and clear, but the

opposite side, the one normally featuring the king's effigy, is completely

smooth and blank. The edges of the coin begin to taper immediately

and continue for about 5mm all the way around. The edges are slightly

convex. The weight of the coin is approximately 3/5 of a normal 3d coin.

I can only surmise that this was the bottom coin of two blanks struck

simultaneously. There is absolutely no evidence of grinding or machining

and the patina on the coin probably dates from the war. The reverse

design is perfectly centered.

Can anyone tell me of similar coins, or how else this coin might have been

formed? Can anyone refer me to an authority on such coins. It simply must

be some type of mint error, but I have never seen the like and I've been

collecting since 1958.

Thanks

[Chris Perkins]

If it was a mint error there should be a raised rim around the edge of the blank side, as the blanks were most probably prepared like that before striking. I'd say that it had been machined and then the evidence of it being machined had been worn away. Impossible to say for sure, you'll need to post a picture.

[Coppers]

If it was a mint error there should be a raised rim around the edge of the blank side, as the blanks were most probably prepared like that before striking. I'd say that it had been machined and then the evidence of it being machined had been worn away. Impossible to say for sure, you'll need to post a picture.

In addition, the fact that it is of only 3/5 the weight of a normal coin argues against it being a case of two planchets struck at the same time. The only other possibility would be a complete delamination (i.e. the planchet split in two after being struck), but as the surface is completely smooth, that scenario is most unlikely and so Chris' suggestion of it having been machined or smoothed down in some way seems the logical conclusion.

[barzilla]

I'm trying to get my scanner working so I can send a photo. I am a tool and

die maker by trade and I can say, without reservation, that this thing has no

toolmarks of any kind. I thought that perhaps the soft brass of a lower

of two blanks might have been swaged out of the collar somehow and sheared off by the die itself. The coin isn't worn enough (barely, at all) on

the legible side to make me think that the opposite side would be any

worse for wear.

As I mentioned, the tapered edges are convex and quite uniform. Additionally, the edges are paper-thin where they are full-size and bear

no evidence of being chucked in a lathe, for example. The taper starts

immediately from the lead edge.

Give me a little time to reinstall the software on my scanner and I'll forward

a couple of photo's. Meanwhile, say for the sake of discussion that this

is legitimate. Has anyone ever heard of such a thing? Thanks

[barzilla]

How's this?

[barzilla]

And this.

[mint_mark]

Has anyone ever heard of such a thing? Thanks

I think we need someone familiar with minting machinery... otherwise we're just guessing what could have happened.

But since we are guessing, is the smaller side exactly the same size as another coin, say, a sixpence or a farthing?

[barzilla]

I measured the coin with calipers and the small diameter is

approximately 17.78 mm.

A 1944 farthing measures approximately 20.17 mm diameter.

A 1944 sixpence measures approximately 19.35 mm diameter.

The coin measures 2.24 mm in thickness.

A 1943 3d measures 2.59 mm in thickness.

[mint_mark]

Hmmm, too big for a silver threepence as well... about the same size as a maundy fourpence though

Surely the reduced weight and thickness indicate that it is not a complete brass 3d blank, and there were no other nickel brass coins made at the time so it has not been struck on a blank intended for another coin. That just leaves the possibility that they accidentally made nickel brass blanks of the wrong size and struck it without the obverse die in the machine ?

I have seen pictures of modified brass 3d coins that have a secret compartment inside... the coin had been sliced in half and there is a join around the edge. Maybe this one was modified to fit into something?

[mitch91]

I am thinking like mint mark maybe it was cut down to fit into something like on a chain.

[barzilla]

Well, not to discount any possibilities, but the border isn't quite concentric

as it would be if turned in a lathe or grinding machine. Besides, machine

processes leave tell-tale evidence in microscopic scratch patterns or tool-

marks. Furthermore, there are no edgemarks where it was mounted into

jewelry. Besides, the easiest way to mount a hanger to brass is to simply

solder it on. In my opinion, it was swaged (squished) into this form. I have

seen most machine processes in my past 40-year career as a machinist and

tool and diemaker. This item shows no evidence of any process which I am

familiar with, beyond swaging. If two blanks were loaded, one atop the

other, and the press closed under pressure, then either the collar would

split or break, forming a broadstrike (not this case), or, if the material was

soft enough, it could be swaged to the outside of the die until the die was

completely closed, which would establish the edges by shearing and trim

off the excess material to the outside. Of course, that would leave a

corresponding "cupped" partial blank bearing the obverse. Considering

that the thickness of this piece is .088" or 2.24mm and the normal 3d

thickness is .103" or 2.59 mm, I could easily imagine the corresponding

piece being so thin (.015") that it was either destroyed in the process or

discarded by the mint when discovered as scrap, along with the excess

material from the double blanks, which would have necessarily had to

be cleaned out of the coining press in order to continue normal operation.

My question, to you fellows, is whether any of you have seen or heard of

such a thing. If this curio should turn out to have any value, my 90-year-

old mother could certainly use a small cash infusion. I think that I mentioned

that I've been collecting coins since 1958. I'm just mostly unfamiliar with

British issues except for the ones contained in this small accumulation.

Better yet, is there someone, there, in England, who could authenticate

this piece? Someone who wouldn't charge more than a reasonable fee

for doing so, I mean.

I've seen hundreds of double-strikes but never one that wasn't misaligned

somehow. This piece is a mystery to me. However, I will state unequivocally

that is hasn't been turned in a lathe nor ground with any type of stone

which would have been available in 1945 when my dad returned from

military service and that is has sat, unmolested, in one dresser drawer or

another in my mother's house ever since, along with several other GB coins

from that exact era. I do not know where my dad was stationed, only

that he was a military policeman in the US Army Air Corps during that time.

If any of you know a collector of coin "errors" it might be helpful to contact

him. Any and all input is much appreciated.

[Chris Perkins]

This chap is a former Queens assay master, and Royal Mint employee, he's your man. Please tell him I sent you:

http://www.coinauthentication.co.uk/index.html

Remember though that British errors really don't usually sell for all that much. The other month I ebayed an aluminium 1976 1p and it went for £20 - £30 if memory serves!

[barzilla]

I turned the coin over to Ken Potter, who is a well-known coin error

expert. Coincidentally, we share the same employer. I sent a scan

over to Fred Weinberg in California and he ventured that the coin

was machined, but 64x magnification shows no tool or grinding

evidence. Ken will figure it out, no doubt, but he did say that he

had never seen the like in his 45 year numismatic experience. He

labelled it a "monostrike obverse" which is new terminology, at

least to me. 64x shows tiny cuds of material on the bevelled edge

portions. I'll post the results after I next see Ken. Thanks for all

the input.