A while back, I asked about enlarging holes in 1/4" thick stainless plate
(Type 316). Here's a summary of the job I've been tasked with:

There are forty-four stainless square support posts. Each post has a base
consisting of two pieces of 1/4" thick stainless angle plate; the plates are
welded along the bottom of the posts, one on each side. Like this:

H
H
_]H[_

The two horizontal flanges that make up the base each have two holes (four
holes per post) for bolting the base to a concrete pad. The holes were
drilled 1/2" by the factory, but need to be 13/16". That's where we left off
in my last request for advice in this newsgroup.

Now I find out the job might be trickier.

Two of the holes may be too close to the forward edge of the plate after
enlargement (still awaiting further info from the customer). If so, then
half the holes (88 of the 176) will not only have to be enlarged, but will
need to be offset so that the resulting enlarged hole is no closer to the
forward edge of the base plate as it is now.

Any ideas on the best way to do this? I have access to a Rong Fu Mill-Drill.

If this were plain carbon steel, I'd probably use an end mill to "drill" the
hole on a new center. But I'm not sure how well that will work with 316
stainless.

Thanks for your advice!
Michael