Pianotech

Working on a Charles Walter upright-- Damper rod appears to be twisting.  Treble dampers lift well, but the lift gradually decreases toward the bass until the bass dampers barely lift at all.  Pulled the action, tightened the hook brackets, inspected the hooks, all seemed fine.  When I lifted the bass dampers out of the way, the treble dampers lifted fine, but with the added weight of the bass dampers the treble rod seemed to be twisting under the extra weight.  Walter says they've never seen this before, but I find that extraordinary.  Their techs were all out of the shop when I called them earlier this week.  Now they want a video (on a piano an hour away).  Is it possible that the rod itself is twisting when the extra weight of the bass dampers is added?  As a temporary measure, I shimmed the connection between the treble and bass damper rods until we can complete a better repair. 

It's not likely the rod itself is twisting.  More likely that the hangar brackets (L shaped thingees) are not aligned or loose, or the hangar flanges are broken, loose, or the felt inside is deteriorated.  I once tried to bend that rod, different brand, but unless it's heated it's not going to bend.  I'm not a fan of those split rods because they are prone to problems like this.  All the parts have to be very rigid if it's going to work reliably.  Take the rod out and sight down the brackets to see if they're in a straight line, correct as needed.  Make sure the flanges are tight on the rail, and any material that might have been placed between the two rods (cushioning?) is still there.