Machining Question: Reaming and Hole Position, Need some grounded "hunches".. Options

[Brian Mifsud]

I've been offline a long time, but I know there are knowledgeable machinists in the forum.

I have several 316 Stainless Steel castings where the hole for the shaft needs to be very accurately located on the centerline to prevent imbalance. This is an impeller that spins at 1200 RPM. The shaft hole has been bored on a lathe to
.4981". The nominal hole size is supposed to be .4987 +/- .00025". The shaft which is supposed to insert into this hole is .4985".

I have a .4990" cobalt tipped, straight flute reamer.

Question:

If I don't get the reamer to bore position dead co-axial, will the reamer change the hole POSITION?

HOLE SIZE:
I understand that the reamer is built to -.0000 +.0002", so in theory, I'd be taking up to .4990 + .0002 = .4992 Reamer Size
.4992 -.4895 = .0007" clearance on the shaft to hole.

But in removing that material, will the reamer follow the path of least resistance and stay dead co-axial to the bore location?

Any variance off the impeller center axis cauese imbalance.

Thanks

Brian