Pianotech

For newer agraffes that are hard to find replacements for, I found new tools for reaming the agraffe holes. What I was looking for was reaming specs that were good matches for specific agraffe holes.

What I did was use wire size drill bits to find out the agraffe hole diameter. I then chose "chucked reamers," straight fluted to increase the hole diameter a very slight amount.

Then, for counter sinking, I found what is called a center drill, in this case "radiused" meaning it has a radiused countersink rather than a straight part.

I found all these items on Grainger.

My method will be: first ream the hole a very minimal amount. Then, counter sink with the radiused center drill, using one that is slightly undersized at the tip.

The reason there are two steps is that center drills commonly come in fractional inches, so I chose 3/64" and then much more precise straight reamers for exact hole diameters.

My goal is to eliminate (only just) the wear-nick or groove inside the agraffe hole that starts where the string contacts and then rolls around up the countersink toward the tuning pins.

If anyone wishes to see photos of how this process will be done, set up at two drill presses, I'll return to this thread and share photos.

I appreciated the Schaff / Pianotek offering of one reamer but after measuring the Yamaha agraffes I was dealing with, I knew that the 1/16" diameter center drill offering wasn't precise enough of a fit. Plus once I found radiused center drills - that was a great advantage. You don't want any sharp step from the initial hole to the counter sink so a radiused cut was ideal.

Yamaha agraffes at least the ones I'm dealing with are not to be found from a regular supply house in the US insofar as I'm aware. However, when I replace pinblocks and string pianos, I like to replace agraffes. This will be the option when agraffes are rare yet in a condition that reconditioning is a good option. Which I will also note,  happens to be the case on old vintage M&H grands as well.

I hope this info helps someone else at some point