OK, let’s see if I can get thru this without losing the attachments…
So after a lot of playing around, I have had to SHIM the backside of the leadnut mount part (for lack of a better name). I did it on both sides of the machine. The two rear screws each got 2 washers, and the 2 front ones each got 1 washer. This helped a lot in getting the aluminum plates square to the frame and each other.
That didn’t quite get the top rod to line up side-to-side for some reason, so I got out a drill bit and took just a hair off the hole - you can see the scraps, not much was removed. But that really, really helped a lot.
Then I tightened everything up - AND IT WAS BOUND UP AGAIN!!!
So more investigating, and I see that the leadnut mount part IS NOT FLAT on the leadnut!!! Off by 16 mils (feeler gage shown)!!!
So, what to do? I pulled one washer out from behind the front top screw that I just shimmed in (so now no washer), and took 1 of the 2 washers out from the rear top screw - so effectively putting a twist into the leadnut mount part with respect to the aluminum plate. Now the leadnut sits mostly flat. So I tightened up the 3 M5’s and…I could still bind up the leadnut - but it took some doing. So I loosened up the 3 screws - and it works perfectly! I would post a picture, but it looks like 6 is the site limit
So, moral of the story - it’s those 3 M5 screws that are torquing the leadnut and causing all the grief. I am able to leave 1 tight and 2 loose, and no grinding, and free moving axis.
Now I have to figure out why I have Z Banding - surely related to all this mess.
Good luck all - hope that helps.