If you really want a shrinkage rule, just draw a standard 12" ruler in CAD, and then plot it to whatever multiplier is required for the various metals. You can print it on card stock and then laminate it in plastic.
Well now why didn't I think of that??
Thanks UNIcastings
For those of you who don't have a CAD program, attached is a PDF of a 3/16" shrinkage ruler.
John
View attachment 3:16 Shrinkage Ruler.pdf