I might be able to help here, I have the original part for my machine but I will need to hunt down where it is, as I'm in the middle of restoring the whole machine (unfortunately, mine found itself on its backside durings its last move....). It looks like your machine suffered a similar fate with some of the machined parts for the tapering jig? The cast pieces on mine are currently on the healing bench with JB Weld. Just about scrapped my whole machine. The biggest struggle is straightening the "telescopic screw" which bent to a 45deg angle in the fall.
If possible, could you also share some detailed pictures of the bracket that attaches to the ways for the screw, my machine is missing that piece so I'm interested to know how it attaches and clamps to the ways.
There is a diagram in the manual for the machine showing the part. It's a simple threaded rod with two knurled hand wheels.