Print this page at 100 per cent and put your coin on it. Every circle is drawn from a diameter stated in a document, and no circle is drawn for a coin whose diameter we cannot source.
This bar is 100 mm. Measure it.
The Coinage Acts set a coin's weight and its fineness and say nothing at all about its diameter, so for most pre-decimal coins there is no statutory figure to draw. Rather than copy a number from a hobbyist table or scale one off a neighbour, these are left undrawn. Their weights are exact and are enough to identify them:
| Coin | Era | Statutory weight | Fine metal |
|---|---|---|---|
| Threepence | pre-decimal | 1.41379 g | base metal |
| Sixpence | pre-decimal | 2.82759 g | base metal |
| Half sovereign | gold | 3.99402 g | base metal |
| Shilling | pre-decimal | 5.65518 g | base metal |
| Halfpenny | pre-decimal | 5.6699 g | base metal |
| Sovereign | gold | 7.98805 g | base metal |
| Florin | pre-decimal | 11.31036 g | base metal |
A kitchen scale reading to a tenth of a gram tells these apart, and colour settles the two near-collisions. See what have you got for the full weight ladder.
penny, from a minimum of 1'21 inch to a maximum of 1'22, from the report for 1913, page 7.
It may he of interest tolstate that the diameter of a new penny may vary from a minimum of 1'21 inch to a maximum of 122
The Royal Mint states this as the range a NEW penny may measure, in the course of explaining that telling machines were gauged to reject pennies over 0.08 inch thick. It is a manufacturing tolerance, not a statutory figure: the Coinage Acts fix weight and fineness and say nothing about diameter.
crown, 1~52 inches, from the report for 1928, page 21.
a. diameter of 1~52 inches, the size of the crown piece, was selected, and no difficulty was experienced in striking these m
Given while explaining why a Perth medal was made at this size: it had to be struck in a coining press, so the crown's diameter was chosen. The crown is named as the reference, which is what makes the figure usable.