The difference between the actual casting dimension and the theoretical casting dimension calculated from the shrink rule
Second, the question of shrink rule
on DI patterns was an issue.
Calculations similar to those above indicate that a scale or shrink rule
can only be used to measure patterns in which the casting feature tolerance is at least 0.
The layout or drawing is always drawn to full size, though generally not dimensioned, but having great accuracy and incorporating the shrink rule
Patternmakers use a shrink rule
," a special linear scale different from a regular ruler.
In far too many foundries today, the belief is prevalent that the correct application of the shrink rule
can solve dimensional accuracy problems.