38.4mm in diameter x 2mm deep edge... The edge still retains the edge the original coin was made with... Which looks like circles and squares alternate. The inner rotating part is about 25.3mm dia... And the item weighs 22.7grams.
The very top of the reverse of the coin has been machined away and then engraved with the details you see on it now.. The central part has been machined away deeper to allow for the central days engraved part to sit into and turn on the simple screw in the centre.
Very fine skilled work and you will love it.. But it is a really fascinating item and I wonder where in the world it was made and who for and where it has been in its hay day whilst being used and then of course put in a box and forgotten about for at least a 100 years.... My measurements are done with an electronic digital caliper and small weighing scales.
The item "Silver 1781 Perpetual Calendar made from Carolus III Spain 8 Reales Coin RARE" is in sale since Saturday, March 21, 2020. This item is in the category "Antiques\Silver\Solid Silver\Other Solid Silver". The seller is "diggerlee" and is located in Yorkshire. This item can be shipped worldwide.