Sixpences on Numista, dimensions double but purity and weight remain the same?

[mik]

This had me confused. I have a 1757 sixpence. .925 silver. I measured the diameter as 20.85mm, thickness as 1.02mm and weight as 2.97g.

Numista gives the thickness as 0.5mm for the 1757.

Then I looked at a couple of other sixpence years on numista and noticed that the thickness was 0.5mm, diameter 19mm for George III and thickness 1mm, diameter 19.3mm for the Victoria....although the weight for both sixpences was 2.83g?

I'm guessing the mass is the same, but the thickness is maybe a measurement of the highest prominence. I mean like the thin 0.5mm coin is low relief and the thicker 1mm coin has higher relief in some areas.

Still my thickness measurement of my 1757 sixpence seems a bit out. I hope not, but I'm open to the possibility it might be one of those AliExpress nutsack coins. 

 

[SidS]

Well first and foremost, your sixpence is genuine, no worries there.

From 1816 the standard measurements are diameter of 19.41mm and 2.83g - the varied weights and thicknesses at numista will be down to wear. Very worn sixpences can be half as thick etc.

The 1674-1787 era sixpences are a little more varied. Coins were struck with weight being the primary concern. The flans can vary in diameter and thickness quite a bit. This in part was due to the technology of the time, cutting blanks so they weighed correct rather than machine cut precision etc. Things just weren't standardised as they became with the commencement of steam driven presses used by Boulton and Watt from 1797 with the cartwheel copper coinage. I've got a pile of these sixpences and when stacked up they're all different diameters, the thicknesses vary as well but these are less noticeable.

Sixpences were struck to be approx 3g, obviously with wear it drops, so 2.97g is perfectly respectable.

[mik]

18 hours ago, SidS said:

Well first and foremost, your sixpence is genuine, no worries there.

From 1816 the standard measurements are diameter of 19.41mm and 2.83g - the varied weights and thicknesses at numista will be down to wear. Very worn sixpences can be half as thick etc.

The 1674-1787 era sixpences are a little more varied. Coins were struck with weight being the primary concern. The flans can vary in diameter and thickness quite a bit. This in part was due to the technology of the time, cutting blanks so they weighed correct rather than machine cut precision etc. Things just weren't standardised as they became with the commencement of steam driven presses used by Boulton and Watt from 1797 with the cartwheel copper coinage. I've got a pile of these sixpences and when stacked up they're all different diameters, the thicknesses vary as well but these are less noticeable.

Sixpences were struck to be approx 3g, obviously with wear it drops, so 2.97g is perfectly respectable.

Thank you, so much, that puts my mind at rest. I did notice that it wasn't engineered perfectly round like a modern coin. I've never had a coin this old, or with as much character and olde world charm. I can almost smell the history wafting from it! 😀

[mik]

I'm hankering after a 'LIMA' one now...no one told me how addictive collecto-stacking would be.

[SidS]

Careful, early milled is definitely a rabbit hole you could get lost down...

I fell down some time since and ended up with this lot:

 

[Petra]

3 hours ago, SidS said:

Careful, early milled is definitely a rabbit hole you could get lost down...

I fell down some time since and ended up with this lot:

 

🤔get em melted 🤔😮😂