upright trapwork, experience drilling metal queery

[AKarab@aol.com]

Hi all,

In an old upright, I am considering removing the sustain pedal vertical
dowell's guide arm (anchored to inside side of case left of action, with a
hole in the end for the dowell to pass through) and replacing its silly self
with a pin in the top of the dowell that would fit into a theoretical hole in
the damper lift rod lip.

Background: Two years ago I lined up the geometry on all the pieces for this
pedal as best as I could, but the arc the dowell travels still creates
friction problems that tend to work the arm loose and wear through bushing
cloth.  (At the moment it is tacked down with CA glue as well as screwed in
with long screws)

More background:  I have seen one other piano where someone made this
modification, successfully drilled the hole and all, but left the guide arm
and all its problems hanging there.  It eventually became a percussion
section of its own, and is now out of there.

Questions: Regarding this theoretical hole, exactly what is it, cast iron or
steel, that I would be drilling through?  If it is cast iron, do I run the
risk of the old metal cracking?  If it is steel, I need to go get a very very
hard bit for the job.  It'll be good to get the damper lift rod off the
action for this repair, as it has become so rough with corrosion that the
contact points with the damper levers all emit little grunts when the pedal
is pumped.  I'm thinking steel wool, polish, and McLube.

Thoughts?  Experience?

Thanks much,

Audrey Karabinus,   Seattle