As you know I'm using the DELTRON Linear LRS3-1. It is wider than the Bosch frame ( 40mm ) and it is not in the center of the printer. I have mounted it with only two of the 4 bolts. Loosen the two nuts and slide the X axis extrusion straight down. Clamp you slide and mark, and drill your pilot holes. Drill with 4.5mm drill bit and tap with a 5mm thread. I used a 20mm Inbus to bolt it to the extrusion and fasten it to the frame.
Ok, I'll do this to save another post with corrections:
I replaced the motor that is in the above pictures with another I had on hand:
The reason being, that last night when I hooked up the stepper drivers it was underpowered and stalled after numerous attempts to tune the motors. Also after a brief period of correct tuning I tested some macro in Mach3 and the motor got very hot, very quick. So it was not meant to be.
The new one performed perfectly right off the start.