GVJeeper,

I cut some half-blind dovetails a couple of weeks ago and as I was
testing the fit on scraps they were loose (so I needed to lower my bit
more). I was making minor adjustments a bit at a time, but it wasn't
looking like it was making a difference. I was running short on the
scrap in the thickness I had already milled so I went for it and
lowered the bit quite a bit (almost 1/4" I believe, can't remember now,
I only remember thinking that it was quite a bit) and sure enough
that's what I needed -- I had started way too shallow and I couldn't
tell that I was improving the fit but too slight to notice.

Just a suggestion.

Good luck,
Mike