[QUOTE=blue^ray;816124]Hmm, not sure if a problem or not but my gantry has a difference of ~0.5mm in height from one side to the other would it be a problem? (Start with a 1.05 gap and end with around 1.6mm gap I determined this by the sizes of alu I could fit under it)

There are a number of things it could be, but I can easily fix it by putting something under the aluminium slides for the X axis (I planned ahead but I was expecting more of a difference).

Now I cannot mount the Z axis till I get the height right otherwise it will be on a 2 degree angle or something like that if I fix it up later.

Too small to worry about?
No its no to small. What you will find is if you do a trench cut or engraving you will find that the cut will be deeper on one side of the table or Y axis to the other...