Howdy,

I've worked up a Belt Drive conversion in SolidWorks for my (inherited) IH mill, that has never been turned on.**

So should the bearing in the new top be angular contact? The old ones just read 6002 nothing else. Undoubtedly very cheap bearings no doubt.
Another thing is the spindle feels a little rough at the bottom when I turn it by hand, like the bearing has grit in it or something. Not sure what it is. I'm thinking of replacing the lower bearing with something a lot better.

Don't quite understand the preload thing. If you buy the bearings do you preload them yourself as you put them in. If so how? I don't mind spending on good quality bearings, just not way too much - like I don't want to spend $750 per bearing or anything like that.



*** The Belt drive will use a Baldor VM3561T 3hp 3 ph. with a Hitachi vector drive, 2:1 poly-v pulleys