The only thing I really graded before high school was math tests, and yes, he did know what his grades were. For other subjects, I did check written work, like math problems, and made him correct the ones that were wrong, but I didn't give a grade. My rationale was that I wanted to make sure he knew the material, but I didn't want to overly bog him down with grades on his daily work. I also wanted to teach him to be extra careful to thoroughly check his work when he's doing a test. I also helped him edit and improve his writing, but I didn't grade that either.
Once high school came around, I had to figure out a way to grade each course. I was able to find a rubric for grading essays in the "Teaching the Essay" book from Analytical Grammar. IEW also has a sort of grading sheet that one uses with their curriculum. Once I saw these, I was able to make up my own grading rubric for subjects that required writing depending on what I expected from a particular course. I make sure that I give my son copies of the grading rubric before he begins the assignment so he knows what to expect.
I've also purchased test books from the book publisher to use for grades if a particular publisher has a test book. When ds was in 9th grade, I got several month behind grading some of his work. I had to work like crazy to catch up, and I learned my lesson. Now I try to grade math and science tests the same day, and I try not to get more than a week or two behind grading essays.
Brenda