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Broken Damper Rail Center Pin

Started by nrichmond, May 26, 2023, 03:13:46 PM

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nrichmond

Hi all,

I have a 74' 88 suitcase that I love to death. The other day, I was playin the hell out of it, and while using the sustain pedal, there was a snap sound and the pedal wouldn't work anymore. Hours of investigation lead me to the screw for the center pin of the damper rail, which snapped as pictured. The other end is now stuck in the wood below (the hammer rail?). I'm not an experienced tech/handyman, so ideally, I'd not mess with it if I don't have to. Could I just mount a new screw below/next to the old one and leave it in, does the tension need to be at that exact angle for the damper rail to function?

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Cormac Long

if you can remove the damper rail side pins or the brackets holding them down, the entire damper rail will come out letting you access the broken screw more easily.

The purpose of that centre pin is to prevent the longer '88 damper rail warping upward when the sustain pedal is pushed. It's adjustment is necessary to keep the rail level and provide an even sustain. From my own experience, the movement on that screw was pretty loose. So I suspect its a threaded screw into a nut embedded in the wood.

So my first approach would be to try and use a small dowel or qtip stick etc with a tiny dab of super glue and see if you can bond to the broken screw and unscrew it. You may be able to do this with the original screw itself.

Failing that, its going to be a drill job or more involved disassembly of the hammer rail assuming the nut section can be accessed from below.
Regards,
   Cormac

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nrichmond

Quote from: Cormac Long on May 26, 2023, 04:34:52 PMif you can remove the damper rail side pins or the brackets holding them down, the entire damper rail will come out letting you access the broken screw more easily.

The purpose of that centre pin is to prevent the longer '88 damper rail warping upward when the sustain pedal is pushed. It's adjustment is necessary to keep the rail level and provide an even sustain. From my own experience, the movement on that screw was pretty loose. So I suspect its a threaded screw into a nut embedded in the wood.

So my first approach would be to try and use a small dowel or qtip stick etc with a tiny dab of super glue and see if you can bond to the broken screw and unscrew it. You may be able to do this with the original screw itself.

Failing that, its going to be a drill job or more involved disassembly of the hammer rail assuming the nut section can be accessed from below.
Thank you Cormac,

That's a really smart idea; I'll definitely try that and report back.

nrichmond

Quote from: Cormac Long on May 26, 2023, 04:34:52 PMif you can remove the damper rail side pins or the brackets holding them down, the entire damper rail will come out letting you access the broken screw more easily.

The purpose of that centre pin is to prevent the longer '88 damper rail warping upward when the sustain pedal is pushed. It's adjustment is necessary to keep the rail level and provide an even sustain. From my own experience, the movement on that screw was pretty loose. So I suspect its a threaded screw into a nut embedded in the wood.

So my first approach would be to try and use a small dowel or qtip stick etc with a tiny dab of super glue and see if you can bond to the broken screw and unscrew it. You may be able to do this with the original screw itself.

Failing that, its going to be a drill job or more involved disassembly of the hammer rail assuming the nut section can be accessed from below.

So I did remove the damper rail with relative ease; trying the glue trick; I think that I overapplied. Long story short, it's now covered with dry glue, and I spent hours trying to grab onto the screw with pliers, tweezers with no success. I am much too impatient with handy stuff lol.

Before disassembling the entire piano, I would probably be safe taking it back to Custom Vintage Keys where it was restored and sold to me, but I'm really considering just putting in a new screw at another angle. The old one was at a near 45 degree angle relative to the hammer rail. There's easily room on the hammer rail for a long enough screw at 70-90 degrees, and I'm not terribly convinced that the angle of tension on the damper rail matters that much. It just needs to be depressed in the center, right? There doesn't seem to be any documentation about this specific aspect about setting up the damper rail, likely because a broken center pin screw is rare (one other post I've seen).  Does anyone have specific experience with this or wanna convince me that it's a bad idea? I could also make pictures/diagrams to demonstrate.

Cormac Long

Maybe get it to a tech to get that broken screw :)

To put in another screw, you'll be threading wood. What's there is a threaded nut and for a good reason. You've snapped fatigued metal already purely from pedal pressure. Wood is not going to hold up as long and that is why it was done using a nut day 1. As for position, the location that is there is the ideal pivot position for the rail. Any other location will not be the right one.

Regards,
   Cormac

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nrichmond

Quote from: Cormac Long on May 30, 2023, 04:45:23 AMMaybe get it to a tech to get that broken screw :)

To put in another screw, you'll be threading wood. What's there is a threaded nut and for a good reason. You've snapped fatigued metal already purely from pedal pressure. Wood is not going to hold up as long and that is why it was done using a nut day 1. As for position, the location that is there is the ideal pivot position for the rail. Any other location will not be the right one.



I'm not all too convinced that there's a nut on the other end; like i said, the screw comes in at an angle to the hammer rail so I can't imagine a nut is installed at the same angle to make it work. You may also see that I found and revived an old thread about the same issue, where Ben Bove said, "you can get away with piloting a new hole" like I was thinking of doing. I do imagine you'd agree with me that it's putting off an inevitable problem that'll require fixing, but going a whole week without my precious Rhodes is driving me insane! Also, I feel that if I mess it up, it'll still be fixable by a tech (who may not be very happy with me about it), so I see it as being of little consequence. I'll still wait for a response from the one who ran into this problem years ago or from Ben Bove on the old thread(I pray he will impart his wisdom, but I know his expertise shouldn't be free).  Obviously this isn't a certain close on this thread; if it doesn't work, I should warn other owners, but thanks for your lended support and advice, Cormac.

Cormac Long

Just looked at Vintage Vibes replacement and you're dead right.. the thread is a wood screw. You should be good to pilot a hole above or below then. There is no nut there. My bad.
Regards,
   Cormac

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nrichmond

UPDATE: through tons of trial and error, the sustain pedal mechanism now works! Hopefully, it's not just a temporary fix, but I'd like to document this for anyone else that may run into the problem.

I went through quite a few screws of different sorts trying to make it work. Two more broke, one of which is still stuck in there, but there's easily enough space for at least one more.

The winner was a #8 - 1 1/2 inch round-head everbilt wood screw from Home Depot.  Seemingly, the biggest obstacle was the wood itself; Even with a pilot hole, none of the screws bigger than 1 1/2 in, would screw in far enough to clamp down on the pin/rail. At some point, the head would strip or break off. My father and I totally dismissed the 1.5 in at first, as it was barely long enough to reach the wood through the pin. We theorized that it wouldn't dig in enough to hold the rail down without popping out, but unlike the longer screws, it would immediately tense down on the rail with a few turns. I actually had to loosen it to get the rail at a reasonable level, and now the sustain actually works better than when I first got the piano.

That being said, I'm posting this hours after completing the procedure, so I'm really tempting fate to prove me wrong lol. But for now, it's playing like a dream again :'). I will update if anything goes wrong but for now, yay!

jimmymio

Not that uncommon for that screw to snap. Location is not crucial just as long as it is somewhere near the center of the KB.So you can just drill another hole. It should hold the rail in place loosely- not so tight as effect the movement of the rail. While you are in there, check the felt underneath the T-bar. If they are too worn it could cause noise when using your sustain pedal.