ok iv just run some tests on the coupler... with 10N it compresses by .43mm im assuming simmilar under tension
the full travel of the coupler is just over 1mm fully compressed
im thinking unless i take a blow torch to the ballscrew (y axis) i should be ok

if not it should run long enough to machine myself out of trouble

i thought id designed this machine to perfection :) however... i snapped up some cheap 20mm profile rails for the Z axis instead of the 15mm in the design and its had more of a knock on effect than i exspected :(

iv got this funny feeling ill be seeing a few more of those before im done :)