fitting a round rod in a round hole

[GMKlenklen]

Hi all!

I'm working on a project for one of my classes, and I can't seem to find an answer to my question:

Say I've got a bearing with an outer diameter of .75"
What size hole do i need to put in my bearing block such that the bearing will sit snug in there and not rattle around? I probably need to know what tolerances are available from my machine shop (like how many decimal places it can resolve, right?). Is there some sort of equation that can be used to figure out the holes for any size bearing?

Thanks!
and I might as well give the link to pictures of this thing...
http://www.facebook.com/photo.php?pi...&id=1310160279
It's supposed to traverse a parabolic path using magnus effect and a 5 foot per second crosswind... thusfar we have gotten blown across the cource before making it up to the inflection point... so we need more thrust. wish me luck?