I wouldn’t hold your breath for any useful info off the guy.
I contacted him with questions etc when I was planning to replace the bushings in my microcarve z, and he was not very helpful at all. In fact he had a pretty shocking attitude towards the situation, and basically completely bombed me off.
I too had some vertical play also, and it turned out I needed to raise the lock collar on the leadscrew at the top, as well as fiddle with the “anti-backlash” part.
After trying various ways to eliminate to play I used a clamp to apply some pressure to the top of the leadscrew and the bottom of the lock collar (obviously with the collar slackened), and then tightened the collar.
The backlash nut or whatever is essentially useless as it is. If you disassemble your unit i’d say you will be surprised it ever worked. The nut is just split into four part way along it’s length, and then a small o ring applies minimal pressure around the very bottom.
I used some electrical tape around the area split into four to apply some more pressure, and superglued the end of the tape so it wouldn’t come undone.
(This may not make a lot of sense Unless you disassemble your unit and see what I mean).
Since doing this I have had no vertical play and everything works as it should. I understand that it’s not essentially a “fix” and more of a bodge, but this Z will be going in the bin if the anti backlash fails or the bushings go again as it’s basically a pos.
If only cnc4newbies z’s were around when I ordered this microcarve rubbish