grinding noise after installing heated bed

The heated bed gets stuck and makes a horrible grinding sound when attempting to initialize and level the printer in preparation for a print. I think I nudged the mounting frame while slipping the heated bed into place and I'm afraid that it's now grinding gears or something.
More then likely your bed is to far to the left or right depending on which side its getting stuck. In my case I was ever so slightly too far to the left gave it a snug push to the right and I was fine. Its a very tight fit for the heated bed but it fits. Also make sure no wires are in the way.
seemed to work on small objects .. i then printed out a bottle seemed ok ... i then tried to print out a more complex stl an all hell broke loose , once again it was hitting the model , shuttering an a loud bang noise , it was so violent the whole machine was jumping ... it lifted the platform an dropped it down the started to print everything 3 -4mm away from where it was suppose to be ... I stopped the print immediately . when i was taking off the perfboard I noticed the bed was slightly rocking front right hand corner an back left hand corner .. I looked at the bolts holding the heat bed to the arm an tired to make sure they were secure , the front bolt was just going round an round an would not tighten at all .. so i took the heat bed off , at that point i noticed the arm itself was also moving up and down about up to 4 mm , I sent a email to the support company here is Australia yesterday but have still to hear back from them.