I always use a test piece of pewter when making stamps or punches. That way,I can check their accuracy,etc. while they are still unhardened,without hurting them.
These leftovers show a stamp for "Delphia",a name I coined for a line of Ancient Greek themed jewelry that we came out with some time ago. This stamp is less than 3/16" wide. The name is less than 1/32" tall. I made a little straight chisel to make it with. Had a number of tries at it before I got it right,it being so small,and having several letters. I wanted this stamp to look "Ancient Greek" in nature. Its saw tooth border was made with a checkering file. The classical looking ocean wave knurl shown in the "how to make knurls" post was also used in this line.
In picture #2,you can see I was perfecting the letter S in the medieval set of stamps I posted a few days ago, and the letter J can be seen almost under a "bulls eye" that became an Art Deco cloud piece when I milled away parts of it so it would interlock with others properly. In the 3rd.picture, there are stamps for Art Deco clouds and lightening that I made,and intend to use on a piece of jewelry when we work out a good design for the theme.You can also see the letters C,and H,for the Medieval set also. I found I had put the Delphia practice piece upside down,so made a separate photo for it. I need to use a tripod,as I always shake the little camera when I push the too hard to press button.
The Medieval letters were about 3/32" tall. Eventually,i can melt the pewter down and roll it into practice pieces again when they get too busy to find a clear spot on.
On silver,the Delphia stamp would not be driven in deep,so would avoid the "pillow" shape you see. AS SHOWN in the thumbnails,these pieces of pewter are double the size of the actual pieces BEFORE you click on them. That gives you an idea of the scale of the actual work.