I run a Latex 365 and a Designjet Z6. My spindles are not interchangeable...there is a length difference between the two machines, but in addition to that, the connection where the spindle meets the machine is different for us. We also have a 3" core adapter on our designjet spindles, but the spindles themselves are 2" spindles with 3" adapter connections.. not sure if this helps, as I am not super familiar with the Latex 315, but I would be cautious about trying to interchange them..