Alex, point taken, however as you point out Mazak is great for complex castings which this item is and you will find it is more wear resistant than you imagine. For a great many years Delapena used this material for replacement shoes on honing mandrel’s and I can vouch for their longevity, indeed they outlasted the bronze ones also available many time over plus they were much less expensive. They no longer supply them in Mazak so now I make my because the bronze ones just Do not last, why Delapena have discontinued them I have no idea?IF it is Mazak which I find suprising given the wear it will take, It would be possible to use the unworn end of the lead screw as a pattern and cast a replacement. Mazak has a very low melting temp and lends itself to complex castings and is cheap hence its common usage.
But Mike you are missing the point A 1953 ML7 is vary different machine to a Super7.I notice that myford.co.uk are selling S7 leadscrew half nuts for £64 and also lead screws for around £185