Steinway M Agraffe - Broke?

[Farrell]

Just made an appointment with a guy with a "loose" agraffe on F above middle C on a 1970-ish Steinway M. I am not very familiar with Steinway agraffes. How would it have come loose? He says the piano has not been restrung. Most likely agraffe head broke off the stem? Threads were damaged upon installation and have stripped out? Which would usually strip, the agraffe or the plate (I certainly hope the agraffe)? Chunk of plate broke off with agraffe (YIKES!) ???????? 

Also, assuming this is going to be a simple agraffe replacement, where do I get a suitable replacement agraffe and where? I seem to recall that Steinway threads are some odd size - is it the 7/32" that Pianotek sells? The guy thinks the piano is about 30 years old - did Steinway always use the same size threads, or should I be going there with a couple different size agraffes (piano is on the other side of town - would like to try and solve problem on first trip)?

Thanks for any insight from you Steinway-experienced folks.

Terry Farrell