[pianotech] Damper spring cord

Joe DeFazio defaziomusic at verizon.net
Thu Feb 11 13:29:07 MST 2010


Hi Noah,

It should always be fairly difficult to pull the flange cord through the flange holes.  Otherwise, it might work its way out later.  

As for accomplishing that, everyone else has given you good advice.  If you do all of the recommended things but *still* can't get it through, just enlarge the hole a tiny amount (I mean a few thousandths only).  You should have an indexed drill bit set, like this one:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=1611

This often goes on sale for about $35-40 dollars.  You can spend much more for a better set, but get a set either way.  It will save your sanity and livelihood quite often.  Choose the bit that just barely fits through the holes, and twist it a few time by hand to ream the hole sides.  In piano work, it's often better to use a drill bit by hand to sneak up on fine tolerances.  I carry a cheap, light plastic-collared chuck with me for that purpose, along with a four-colleted pin vise.

If you get such a bit set but are stuck in the field without it and need to slightly enlarge a flange cord hole, just use a round needle file or rat-tail file.  You should carry in you a kit of small craft or hobby files, like this one:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=468

I am not necessarily recommending this exact set, but get a similar set (even Lowes and Home Depot carry sets).

If you go overboard and over-enlarge the hole (don't do this, but if it happens...), then, after installing the cord, shoot the sides of the flange with accelerator and wipe a tiny layer of thick CA along the sides.  This should be enough to lock the cord in place, but another tech will still be able to work the cord out with a little effort at some later date, if that should become necessary (and, hey, *you* might be that tech!).  If, instead, you get a nice tight fit (as you should), then don't glue the cord in.

The key here is not to treat the flange as some sacred object that must never be violated by human hands;  it's just a little piece of (replaceable) wood, and *you're* the boss!  Do whatever it takes to solve the problem.

Good luck with it,

Joe DeFazio
Pittsburgh

> From: Noah Frere <noahfrere at gmail.com>
> Date: February 11, 2010 11:15:31 AM EST
> 
> I am trying to re-spring a damper flange.  I pulled back the sheath of the cord, cut, pulled the sheath back forward, applied some wood glue and worked the end into as fine a needle as i could, but alas, i could not get it all the way through the hole in the flange....

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