<html> <body> Barbara, While this is a patch of a fix, you may want to consider Pitch-Lock string couplers.  I'm presuming that putting a brass dowel down on the front duplex string silences the duplex noise.  You can couple both outside strings to the center string and then slide the "staples" until you tune a pleasing interval off of the speaking length.  It works to get rid of the noise while you investigate permanent difficult fixes.  Machining in a hardened rod still requires access to the bottom of the capo as far as I know. Good luck, Andrew At 05:13 PM 2/28/2006, you wrote: <blockquote type=cite class=cite cite="">Howdy,   Back to the 8' Seiler grand.  Sorry if I'm starting to sound like a broken record.  Here's the story:  I serviced this piano when it was new.  Not long into its life, it developed a noisy duplex at the low end of the treble section.  I muted it off.  I tuned it for a few years, I moved away...   I moved back.  In the meantime, the piano was restrung.  I started servicing it again a year after it was delivered.  9 months into servicing it, the noisy duplex returned in the exact same spot--but add another note.  I freaked out (not in front of the customer), the customer freaked out, too (not in front of me).  I contacted the rebuilder who said he filed the capo. He and I came to the conclusion (whether we are correct or not) that it is a case of soft cast iron.  I looked up hardening cast iron in the archives.  To do that would mean taking the plate out of the piano and that's not an option.  I'm convinced if I refile the capo, the same thing is going to happen again.    I know there are some pianos that have some sort of rod installed at the v-bar.  Is it possible to do the same with this piano at the capo?  Has anyone done it?  Do you have detailed instructions?  Will someone hold my hand?.....Please?   Thanks,   Barbara Richmond, RPT</blockquote></body> </html>