I bought a 1/2 drill chuck, used a piece of a pipe as an axis, threaded it on a lathe and screw the chuck to the pipe. After several attempts the chuck was in straight line with the pipe and when I turned the whole thing on the lathe there was no wooble.
Then I mounted the bearings and though they fit tightly, when I turn the axis in the lathe grabbed by the bearings the 1/2 chuck wobles. The bearings I got are chinese and they have a certain amount of play. My fantasy was that the bearings would allow the axis spin perfectly straight but the result was far from it.
I'am thinking about purchasing a pair of bearings that have no play at all, do those exist?
I plan to mount everything on MDF for now, with the mdf part in the middle of the bearings and the bearings glued to the axis with Locktite or similar.
you really need to get a rotoray table. all bearings will have some play in them even the really expensive ones. once you start getting into abec bearings the costs go up really quickly. you can try and use tapered roller bearings and then set a preload if you have to do it the way your trying.
I remembered I had this huge old Maxtor hard drive and dismembered it in search for a spindle and it had one very suitable. The HD was 160MB and had 8 dishes, the spindle housed 6001Z bearings, ideal for my project. I used some aluminium parts lying around to hold everything togheder. The spindle has a slight runout but its ok for me. I will be getting a rotary table some time in the future. There are 6 holes in the spindle that were used to hold the HD dishes toghered, I used those holes to attach the spindle.
Another fun project using a hard drive parts is a sander/grinder HD Grinder