[pianotech] Brass rail/plate Threads?

[Joseph Garrett]

I'm in the process of making some Chickering upright brass plates and I'm
trying to figure out what size threads have been used in the original
applications, the ones in the past and what is used today. Anyone have a
clue? I have some screws that came with various replacement plates and I
have a bunch of screws that came out of an original piano brass rail
applications. Each one is different! Yikes!! I have identified one as 3-48
threads and another as 3 x 0.5mm, (I think, but not sure, since I can't
find a tap in that size!).<G>  The real question is the third one, which I
have scads of along with the scads of "standard" replacements plates which
I cannot identify in correlation with any known thread/bolt size! Anyone
have a clue in this regard?
I've called Schaff and the one guy, (Rob), who "might know" is out of the
office this week! 
Gosh, I'm having so much fun.
Help!!!
Joe


Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I
http://gpianoworks.com/