My First Agraffe Repair

[Robert Scott]

There’s a 1927 Steinway M whose strings are a little rusty.  Even after 
putting a drop of Protek where the strings go through the agraffe, one of 
them broke off at the threads while I was lowering the pitch of G#2 (a 
bichord).  So I guess I will be doing my first agraffe repair job.

What worries me the most is how to decide whether to put one more 
half-turn into the agraffe.  I don’t want to leave the agraffe too loose, 
and I don’t want to tighten it so tight that I break it off.  Ideally, I 
would like a torque spec so I could use a torque wrench to help me make 
the decision.  If the agraffe is pointing in the right direction, but the 
torque is less than X ft-lb, then I will go for another half-turn.  Can 
anyone tell me what ft-lb limit I should use?  I guess most of you who do 
this a lot develop a feel for how tight is enough, but I  need to get it 
right the first time.

In addition, I also wonder how one goes about centering the drill for the 
easy-out on the remains of the old agraffe so that threads in the plate 
are not damaged.  Should I expect to mess them up and just commit to going 
up from the current 7/32" size to the 1/4" size agraffe by re-tapping the 
plate?  And even if I don’t mess up the threads, it is usual to run a tap 
through them anyway just to clean them up before the new agraffe is 
installed?

Finally, I managed to remove the old bass strings without cutting them by 
straightening them just enough to slide through the old agraffe, so that 
maybe I could re-use the old bass strings.  Is that a reasonable 
expectation?

Robert Scott
Ypsilanti, Michigan