I do not believe you can just "generalize" and say "4 1/2 oz. is equal to 1
cup".
A lot depends on the type of flour you are measuring---is it whole grain or
plain white? Is it plain white or bread flour white? Many of the bread
baking cook books will have an information chapter that explains just what
weight of flour the author is basing the recipes in the book on.
One respected author says 5 1/2 ounces of flour is equal to 1 cup, Many
flour sacks say 4 oz. of flour is equal to 1 cup. I haven't checked lately,
but Cuisinarts used to say 5 oz. was the weight to base their recipes on.
As I make most of my bread in the Cuisinart, I have had good success using
5 ounces of flour per cup. I have also used 5 oz. as the standard for the
cup measurement in my bread machine (West Bend) and had good success.
When I make a sweet roll or bread, I usually weight the flour in at 4 oz.
per cup as I know I want a softer dough.
I don't think weighing takes the fun away from baking---instead it helps
give assurance that the dough will turn out correctly.
I taught bread baking classes for many years and turned out many successful
bakers. I would repeat that I think it is most important to read in the
introduction of the particular book you are getting the recipe from to see
just what the author means by 1 cup.
Gloria Martin
ggmartin2@juno.com