Bent Mandrel?

[nonnox15]

I have a Craftsman 42 inch riding lawn mower. It has a loud vibration. How do I determine if I have a bent mandrel?
Two weeks ago I was checking underneath because it was not cutting grass even. I found one of the blades was loose. :ashamed:
I tightened the blade and when I went to mow my grass this week it is loud and vibrating and still not cutting the grass even.
I have checked and can't find anything loose and the blades seem to be even as I turn them around.
I don't know what else could make the noise and cause it to vibrate. Is there some way to determine if the mandrel is actually bent?

 

[Fish]

If you found a blade loose, then you probably have a problem there. The mounting hole for you blade is kind of star shapes, and you have probably got damaged star on the shaft, and you tightened it back up off center. Take that blade off and have a look.

 

[nonnox15]

Thank you for the advice.:thumbsup:
However, when I checked the blades, I did have them with the star in the hole.
But, when I went to remove the second blade, the bolt came loose with no effort, so evidently it was not real tight.
I tightened it and checked out the mower. It is not vibrating or making as much noise as it was. It also seems to be cutting level as well. :smile:
I do appreciate the help AND this website. It is good to get some help when you need it. :thumbsup: