If you look though the photographs. You will see that the X Axis bearing plate is a copy of the existing plate, bolted on with the same alien screws and is of simple construction. 

 

The Y axis bearing plate is more complex as the Y table has to allow space for the screw and stepper to clear the front casting of the machine. to facilitate this , I first made an aluminium plate to  bolt onto the original mountings, then drilled through this to accommodate the ball screw.

This fabrication was then bolted to an aluminium bock which was channelled out to accommodate the ball screw, and provides the offset from the front mounting plate.

Then finally a 3rd plate is bolted to this to secure the stepper motor.