[pianotech] Agraffe threads out of spec

[Mike Spalding]

Ron,

Never had a problem with replacement agraffe threads.  Lately I've been 
buying agraffes for S&S from Pianotek.  They package them as sets for 
the specific model, at about 60$US.  Includes the appropriate number of 
wide-spaced bi-chords.

Mike

Ron Overs wrote:
> Hello all,
>
> We're currently at the assembly stage of a moderate overhaul of a 20 
> year old US Steinway M. I didn't like the original agraffes with their 
> oversize string holes, so I decided to replace them with new parts 
> instead of re-cutting the original string holes.
>
> The new agraffes have been here for a few weeks. I sourced them from a 
> local parts supplier.
>
> Today was intended to be the 'fitting agraffes' day, but it ended up 
> as the 'return agraffes to supplier' day. Being a US piano, the 
> agraffes threads are 1/4" by 36 threads per inch, but the parts 
> supplied turned out to have a thread size of 6.5 mm OD by 0.75 mm 
> pitch. Has anyone had this experience? The intended replacement parts 
> (ie, the 6.5 mm things), instead of measuring around 0.246" across the 
> thread OD when measured with a micrometer, actually measured right on 
> 0.250", which is just around 6 thou smaller than their 6.5 mm nominal 
> size which would be 0.256".
>
> Anyone out there have any ideas about a possible supplier of quality 
> 1/4" X 36 TPI agraffes, which are actually the intended thread size 
> without oversize string holes?
>
> Since our supplier ordered the parts as being 1/4" by 36 TPI, I'm 
> wondering how many others  there are who have been caught with these 
> out of spec parts. For the reference of others, these out of spec 
> agraffes can be screwed into the plate holes about 3 - 4 turns before 
> they tighten up due to the misalignment of the thread pitch.
>
> Ron O.