On 2008-05-09, dpb wrote:

I'm still not sure where his stringers come into the picture,
however.

I believe that in his first post, the OP stated that he has captive
treads that are fitted into grooves in the two side stringers. So if
he wishes to cut back the tread nosing or overhang, the question is
what to do about the part of the tread that is in the groove of the
stringer.

Cheers, Wayne

dpb -- I'm with you on doing it right the first time around. I'm all
about that. The problem is that this is a cookie-cutter, factory
assembled staircase rather than a custom built one. Which means that
there's tons of glue on the other side. While not impossible to do,
it increases the scope dramatically.

Wayne -- you've hit the nail on the head! Thank you.

The new tread nosing has sufficient overhang incorporated into it; so
I'd rather not extend existing overhang for multiple reasons as stated
by others above. This means I have to eliminate existing overhang,
which translates to trimming existing tread nosing flush with riser.
And this is where my concern lies.

If you look at this picture -- http://www.masterpiecestaircase.com/...ringer_img.jpg
-- the left (routed) stringer is what I have. If I trim tread flush
with that type of stringer, I cannot remove whatever is left of tread
from stringer groove; mainly because the tread is press fitted and
there's a shim on the underside pushing it against the front of the
groove.