Welcome to the forum - but I'm afraid you're in the wrong place to be asking that question. If you read the "stickies" at the top of the forum, you'll see that discussion of mini-lathes and other hobby-grade machinery is not allowed. Why? Because this forum is oriented towards professional machinists. To be sure, us hobby guys (definitely includes me) are more than welcome, and this forum is an incredible resource of knowledge about machining techniques and issues. You can ask all sorts of questions as long as it doesn't mention or revolve around (sorry about the pun) a hobby-grade machine.
Your question is a good example of the latter. Even if you didn't mention the type of lathe involved, the first question that would be asked here is what grade of bearings did you use. If you did not use precision grade bearings - which cost hundreds - then you have your answer. With ordinary off-the-shelf bearings, it is a crap shoot as to what you will get.
You will get much better reception for this question at one of the sites that IS specifically focused on hobby-grade machines and hobby machinists:
The Home Machinist! - Index page or
The Home Shop Machinist & Machinist's Workshop Magazine's BBS.
Meanwhile, so as to leave you with some kind of answer, it is what I said above - as a start, you will have to use better bearings, or at least try more than one set of bearings, to try to get better results. Admittedly, the results you report are *really* bad, even for off-the-shelf bearings, so there may well be another factor. But working on a machine with known inconsistent quality control, using bearings that may come from a similar source ... there is simply no way to know where the problem lies without going through it systematically. Bent spindle is possible, but unlikely if you didn't have the problem before. Could be simply need to try different bearings ... could be a bit of swarf got into the bearing seat when you were assembling ... could be there is a high spot in the bearing seats ... could be ..............
Oh, by the way, please don't be offended if/when this post gets locked - happens to all of us from time to time, and usually happens to us hobby folks early on in until we learn what is and is not appropriate for this forum. Again, welcome!
