just what is 7/32"?

[A440A@AOL.COM]

Greetings all, 
    Here is the deal.  The piano is a 1920 Steinway.  The agraffes have 7/32" 
stems, and they mic out to be either .217" or .218".   The replacement set I 
got from Steinway has stems that are between .209 and .211, PianoTek sent me 
theirs, which were the same, and said that that is all that is available. 
These agraffes are so loose threading in that I worry about them staying put, 
and one of them stripped as I aligned it.   Is there anybody out there with 
full dimension agraffes, or do they really all come from the same place?
    Nossman suggests threading out to 1/4".  I have a natural reluctance to 
begin machining on my only plate for this piano, but if this is a feasible 
approach, and there is something in the archives to shine the light, I may 
have to do this.  
Suggestions? 
Thanks,
Ed Foote RPT