A pattern maker, grader, or you could make the grade rules. It's harder with children's clothing because there isn't as much standardization. An experienced grader should have some standard charts or be able to develop rules off of your measurement charts. I would personally start with the Jack Handford book and make modifications. I would only let a pattern maker do it who has experience with it.
If you have time, you may want to sew up the smallest and largest sizes just to double check the grade and sizing. It doesn't have to be in your production fabric or anything. A fitting is the only way to know if your grade is correct. You won't need to do this on every style or very often. Kind of important when starting out though.
February 04, 2009
Who creates grade rules?
Some one asked me a grading question the other day. She wanted to know who creates grade rules?