[pianotech] Knuckles Replacement - the details

[richarducci at comcast.net]

Joe, do you use anything on the mortice to ease removal of knuckle?
Wall paper remover or something ?



Rick Ucci
Uccipiano.com

On Feb 5, 2012, at 9:50 PM, "Joseph Garrett" <joegarrett at earthlink.net> wrote:

> Just finished swapping out the 10mm knuckles for some 9mm ones. As I was
> doing it, it occurred to me that the fine details might be of use to those
> who have not done this job. So, here they are:
> I removed the original knuckles with Fence Wire Cutting Pliers(slightly
> modified<G>).  As I did, I cleaned the notches and removed any residual
> glue from the shanks & mortises. I did this with Nicholson 4" files, one
> with the sides made "safe", the other left as is. It turned out that the
> "as is" one was .001" thinner than the "safe" one, which was used as the
> final thing to clean out the mortise and size it. The "as is " one was
> exactly the dimension of the mortise. <G> Once all the shanks were prepped,
> then each individual knuckle was fitted for it's shank mortise and the nap
> of the leather was determined. The nap needs to be smooth towards the end
> of the shank and rough towards the centerpin. The "rosewood" of the
> knuckles is not absolutely the same size, nor are the mortises of the
> shanks, so individual "fitting" is needed. Once the knuckle was "fitted",
> it was then glued into the mortise. I use modified clothes pins, (the
> spring type), to add just enough pressure to hold the knuckle at right
> angles to the shank and in the bottom of the mortise, without crushing the
> knuckle. At the same time as the gluing process, I double check for damage
> from the removal of the other knuckles. If found, I press glue into the
> crack(s) and the clamping does a double duty. I have 16 of the clamps, so I
> just pull from the first of the shanks, when I get to #16 I use #1. It
> seems that the cold hide glue has set up sufficiently in this amount of
> time. The work goes fairly quickly, even though I'm doing a bunch of things
> to each one of the shanks, in the process. Once the glue is set, I clean up
> any glue beads/smears on the outside of the joint(s). Of course, in the
> process, I make sure the knuckles are in exactly the proper position in
> relation to the shank/motises.
> Hope that helps.
> Joe
> 
> 
> Joe Garrett, R.P.T.
> Captain of the Tool Police
> Squares R I
>