Some good comments and I do think I need to revise this as I know it will cause some problems, is there any advantages of using this method I do think it is certainly better than mine as it would take an awful lot of cutting force to knock this off its rails

I may result to mounting these this way as its so much easier or to mount them on the inside of the gantry like the Joe CNC again comments or ideas welcome, good god this machine is proving to be hard going!