How can i tell which side a lawn mower blade go's?

Question

I mean theirs 2 sides to a blade so if i am going to put it on,how do i know what side go's up or down?

Answer 1

Sorry about my drawing not showing up properly, but it seems that the system used for typing in answers does not provide a faithful reproduction of the exact manner in which the text is typed.  My text file in ASCII code faithfully reproduces a drawing of a blade using "/" and "\" characters. The spacing is critical to faithful reproduction of the image.  Other forums allow image attachments and such which makes communicating information much more accurate.  
Well, the main point was, as guest 2818 indicated, the beveled side of the blade should be facing the motor (the lawnmower deck) and the flat part of the blade would then be facing the grass to be cut.  Also, if the blade has upward curving ends (tips) then the curve should be facing the deck or motor also.
Sometimes the side of the blade that is supposed to face the grass is stamped with the word "Bottom" (or sometimes just a part number). I just checked my lawnmower blade and the part that faces the motor has nothing stamped on it, but the side facing the grass has G L B stamped on one side of the center hole and an arrow indicating direction of blade rotation on the other side of the center hole.  I hope this helps some.

Answer 2

/     You are looking at    (spin direction) <--- /       the blade from the grass side.         --->/   /
     The deck of the lawnmower is behind  /    /   /
     the blade drawn here.               /    /   /
     ... Blade's edge __________________/    /   /
     The 45 degree bevelled edge            / o /
     of the blade is on the other (hidden) /   /
     side of this blade drawing (facing   /   /
     the motor & deck). The flat part    /   /   (direction)
     of the blade is on this side of    /   /     (of blade's)
     the drawing and it will be         \  /------> (movement)
     facing the grass.                   \/