Some metal from the surface of each blank then passes into solution, and the blanks are reduced in weight with remarkable uniformity.
In the case of very large silver coins only one blank is cut in the width of the fillet, but bronze fillets are made wider so that three penny blanks are cut out at each stroke of the machine.
The blanks are next softened by annealing, and are then thoroughly cleaned before being passed to the coining presses.
The blanks are then passed to an edge rolling machine, by which they are thickened at the edge so as to form a rim to protect the finished coin from wear.
The blanks are converted into coin by receiving an impression from engraved dies.
In most foreign mints the blanks are weighed by the automatic balances before being struck, and those which are too heavy are reduced by filing or planing.
If the weight of the blank is slightly below the standard weight, a somewhat larger cutter is used, so that the blanks may be of correct weight.
The spherical blanks soon gave place to lenticular-shaped ones.
The amount of copper removed from silver blanks containing 900 to 925 parts of silver per moo is from o 6 to I o per 1000.
The blanks fall through an aperture after having been heated for a few minutes.