replacement knuckles

[Dave Mckibben]

Jon:

If you would like to send me the dimensions you would like, I will look
into making one for you.
I could try plexiglass, and aluminum if you would like.

Dave McKibben
San Diego

> [Original Message]
> From: Jon Page <jonpage@comcast.net>
> To: <pianotech@ptg.org>
> Date: 12/3/2004 4:44:24 PM
> Subject: replacement knuckles
>
> One could mic the breadth of the knuckles and group them accordingly
> but probably the main objective would be to press them into the slots
> with a caul to aspire to more consistent results (jpg attch'd).
> Then a further measurement of knuckle height could refine the shank
groupings.
>
> On a new set of shanks, I sort first by shank SW sorting those to 
> sub-groups of knuckle height.
>
> The knuckle_caul.jpg which is attached is the first prototype, made from
> mahogany. Consistent results were not achieved because the wood compressed
> as the procedure progressed. My next one would be made from HMD plastic.
> One machined of metal would be cost prohibitive for my purposes.
> Here's a tool waiting to be produced... Joe, ... Bill, ... anyone...
>
> I have used the caul to compress the knuckle to conform to a tolerance
> but have not followed up on measuring after a few years.
>
> I maintain a .010"/.25mm window of tolerance for knuckle height with the
bulk
> in-the-middle (say ~.640") and hi's (.645") & lo's (.635") off to their 
> respective sides.
> (Shank height does not vary enough to be a consideration).
>
> By grouping the knuckle heights, a smoother regulation is attained; one 
> item evident of this
> is a straighter let-off button alignment.
>
> Just one of the plethora of hair-splitting, nit-picking details which 
> consumes our work hours.
>
> I'm tired just thinking about it.
>
>
> Regards,
>
> Jon Page, piano technician
> Harwich Port, Cape Cod, Mass.
> mailto:jonpage@comcast.net
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~