Well, Jeff, like I wrote in the previous post: most of them render fine. (And yes, of course I'll leave those alone!) But I did mention that there are 4 or 5 others that also have high rendering friction, and I do feel that I need to treat these - a.s.a.p. (if only for my nerves' sake when tuning the next time).

I'd never heard of crocus cloth - will ask in the local hardware whether they have it. Would you think a pipe cleaner with metal polish would also work?

By the way, my parents' Ibach, practically identical, has had several of these termination pins replaced. I now have a hunch why...

I don't think a pipe cleaner with anything would do much.

I was thinking of feeding it around the pin, similar to a string, and pulling to-and-fro on the opposite ends while applying tension (just like the string moves while tuning), using some polish or abrasive paste.

What more would fine abrasive cloth (which I gather crocus cloth is) be able to achieve?

I can see the pipecleaner maybe making the surface shiny, but not removing file marks. And if the pipecleaner (or anything else that is wrapped around the pin) did take much material off, it would make the radius of the bend smaller, not larger. Fine emmery cloth, or even a strip from a fine sanding belt should work well, too. You could probably skip the file this way.

Hopefully someone who has actually done this will chime in.

I lubricate upper bridge pins with Protek frequently on older pianos with rendering issues. I've never had a problem with it, and it can noticeably help. I apply it with a very small gauge hypo-oiler. You can really control how much comes out, and it comes out in very small drops.

Jeff,

I'm still not sure I see how the taut pipe cleaner (coated with metal polish) would be so different from a taut strip of fine emery cloth, in terms of geometry, radii, etc..

But anyhow, I'm the one looking for advice, so I'll step back and listen.

Perhaps with "radius" you mean the arc that's in a plane with the termination pin, not the arc of the string that's in a plane with the soundboard?

Ryan,
I have access to very fine syringes, so the application of Protek is no problem - as long as it doesn't creep down the string and mess up the copper windings.

Feedback for those who may be interested:

I used a strip of fine emery cloth, about the same width as the free length of the termination pin, to take the worst string imprints out of the pin and the worst grinder burrs off of the V-bar. The pictures show the steps.







I couldn't get it much better and didn't want to remove any more material. Hopefully it's good enough to run with normal friction now.