Reading the manual last week to learn more about the mtc for this mower; i came across the subject of replacing blades. Now, I don't have the manual in fron of me but it seems that I remember reading about adjusting and tightening the bolts to a certain pound measurement. As if I would need a special tool to determine that the correct force was put on the bolt to ensure that it's tight. Do you all do this, or do you just tighten until it can't go no more???