Please help! I can't tighten the nuts on my new exhaust fan motor in my bathroom!?

Thank you all so much!

The motor with the screws on it is brand new, so I don't see how they could be stripped. I put the nuts back on the old motor and they seem nice and tight. So I think My Nom may be right about it being metric or something. The new motor didn't come with nuts and the instructions don't specify any size. I hate to take the motor back out and to the store, so I will take one of these nuts to the store and see if I can match it with equivalent metric size. Thats really cheap not to include new nuts!

If that doesn't work, I will try the other answers. Thank you for taking the time to help me with this!

Sounds like the bolts are stripped. Take it back and get another one or purchase a tube of Threadlocker Red and put Threadlocker on the bolts and then tighten them as tight as you can then stop. Do not use the fan until the Threadlocker has totally dried. You can get Threadlocker at most auto parts stores.

http://www.amazon.com/Permatex-27100-High-Strength...

You overtightened and pulled threads off. You can put a couple washers under each nut to move it to better threads. Could also use thicker nuts. If you can, take ut back, but they'll see that you abused the situation.

Are these the original nuts / bolts? Or is "half" of the problem metric?

Just saying.