I'd like to get pointed in the correct direction for the following problem at my job.

Currently we have an older model Chevalier knee mill that's been converted to 2 axis CNC with Proto-Trak Edge controlling it along with all the hand wheels still.. About 2 months ago the Y axis ball screw snapped at the machined step in the screw for the angular (assuming) bearings at the front of the machine. After contacting Southwestern Industries I was given a part # to order a new ball screw and nut for this machine.

Once it showed up, I spotted quite a few differences that makes my not want to try to use it
-Around 2" too short in the machined end
-The machined bearing area of the shaft is shorter than the original
-The ball screw portion is about .5" shorter
-The ball nut is twice as long (not an issue unless once on the machine it risks coming off of the end of the screw)
-The ball nut flange has two holes within 45* of each other rather than the original with 2 holes 180* from one another.

My next attempt was to contact Chevalier. Due to the machine's age they had to talk to the factory in Taiwan they said. Upon hearing back, I'm told the machine is too old and the ball screw and nut for that model are not available.

So, that puts me to where I'm at now--playing maintenance man and trying to fix rather than ditch a useful machine.

It'd be nice to send back the wrong ball screw to SWI and put $900+ back into the company's pocket. Can this broken ball screw be successfully fixed based upon the location it was broken? I can tig weld it but worry about changing the metal strength and also keeping the two pieces concentric. It obviously broke in a location under a lot of load if the machine is crashed in 1 direction so strength is important.

I'm also told by SWI that sometimes extensions are given for adapting new ball screws to older machines. Taking the broken machined part of the old screw, cutting it down, drilling/tapping, and then adding that to the new screw could possibly re-allow the use of the hand wheel and measuring ring as before. The ball nut flange can have a second mounting hole drilled in it no problem too. Is this extra work worth it though.

Thoughts?

Below are pictures of said ball screws and the machine.
Attachment 362446
Attachment 362448
Attachment 362450
Attachment 362452
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Attachment 362456
Attachment 362458