1955 threepence - struck on a rolled thin planchet ?

[JLS]

I recently picked up this 1955 threepence which looks about 60% of the thickness of the standard issue. No signs of post-mint damage, but clearly got into circulation. Is this a thin planchet error or something more interesting ? 

Weight is 4.5 grams instead 6.8 grams.

Photographs (including comparison with regular striking): https://imgur.com/a/tj0iU5t

[Peckris 2]

To my mind it's a thin planchet, though how is another matter. It's clearly not post-Mint as it's fully struck up. Interesting.

[1949threepence]

Very interesting - and I assume recognised many years ago, as the accompanying note has clearly been typed on an old fashioned typewriter, and the paper now yellowing slightly.

Precisely how these anomalies occur is anyone's guess.   

[Mr T]

Correct diameter?

[PWA 1967]

Possible lamination error before the blank was struck or a blank intended for a different coin ?

I believe the sheets were rolled together causing one sheet to join another of a similar thickness.If they did not join the blank would be thinner but the same size diameter ,although ones i have seen tend to be more weakly struck.

Either way if the coin is thinner it obviously wasnt the correct thickness when struck as cleary shows the design on both sides ( apart from the daft acid things PM ) ,so either lamination or a blank meant for a different coin mixed in with the others.

[JLS]

On 1/5/2019 at 12:01 AM, Mr T said:

Correct diameter?

Yes - exactly the same diameter as the standard issue. 

On 1/5/2019 at 2:33 AM, PWA 1967 said:

Possible lamination error before the blank was struck or a blank intended for a different coin ?

I believe the sheets were rolled together causing one sheet to join another of a similar thickness.If they did not join the blank would be thinner but the same size diameter ,although ones i have seen tend to be more weakly struck.

This is the only thing which really surprises me about this coin - there seem to be no problems at all with the strike - it is sharp everywhere, albeit clearly a little worn from circulation. I can't think of any other 12-sided coins the Royal Mint would have been striking in 1955...so I guess it was just lucky ? 

[VickySilver]

I have run across numerous 3ds from this era that were either a bit thin or thick, so interesting but IMO not that rare or valuable.

[Mr T]

The Fijian threepence was the only similar coin struck at the time but it was 6.2g

I'll agree with struck on a split planchet.