Pianotech

Hello PTG community, thanks in advance for offering experience or advice regarding my following questions! This is my very first online discussion post. I have cross-listed to the CAUT forum, so apologies if you see it twice.

I am curious how to proceed with the following piano that is located at UCLA (one of the institutions where I work). This piano has fairly severe bridge cracks in the high treble section. The cracks appear to only affect the rear bridge pins. The bridge looks to be made of two pieces: a root (apparently laminated) and a cap. It was difficult to photograph the end of the bridge, but it looks to me like the crack goes through the cap and even into the root at the very edge.

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Joshua Sadinsky
Santa Clarita CA
https://pianojosh.com/about
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I have only done a few repairs like this and mostly on less valuable pianos, so I would listen carefullyto other's opinions.

You can get a hand screw clamp onto this bridge if you remove the strings (just pull them aside):

https://www.amazon.com/POWERTEC-71524-Wooden-Handscrew-Clamp/dp/B07W1P4XJ1

It might be possible to get a drill through the bridge from the side.  You may need an aircraft drill bit, but it might be accessible from under the plate.  I have  bolted spinet bridges together with a small machine screw, but you could also use a hammer shank bit and dowell the bridge together with a hammer shank.

If you are glueing it together, epoxy or Titebond would work.  I trust Titebond more than other technicians do, but most recommend epoxy.

Capping would be better, but that presupposes that you are competent with wood working to craft a decent bridge cap (I am not).

I will mention that I had a similar experience with a '90's vintage C3 a local teacher had purchased "used." In that case, the end section of the bridge cap was clearly a faulty lumber issue, and was a different color than the rest. No bridge splitting involved.

Even though the piano was out of warranty, I suggested that she send the photos to Yamaha, and they chose to send technicians out to add new capping material and bridge pins to solve the problem No cost to my client. I was impressed with Yamaha's commitment to service an out-of-warranty piano problem.

since you are at an institution in LA, it might be worth sending your photos to Yamaha? can't hurt.

Regarding tackling the repair yourself, my experience would suggest it's not that hard, depending on how much capping you need to replace. If we're talking 6 inches or less, it's pretty simple to remove the strings as required, then chisel off the defective cap material carefully. Once that is accomplished you should be able to get some small c-clamps to pull the bridge back together? I agree Titebond would be sufficient, but epoxy is very popular. Get some quality bridge capping maple, make sure it fits nicely in all dimensions and drill a few small holes to clamp it down to the repaired bridge.

Install each string individually, lowest to highest. Pull string carefully up to full tension, then mark right next to the string for rear pin location. Again follow string to front pin location, and mark on the other side for gentle but positive side bearing. Again remove the wire then tap your marks with an awl and drill correctly for bridge pin diameter (snug but not too tight.) You can use hole as a guide to chisel angle clearance from center of  hole. Same on front side. Confirm your pin hole depth gets you into the bridge around 3/8 to 1/2 inches, then tap in pins. When they're all installed, file them down as required, re-install all wires and tune a few times.

Hopefully you can get paid correctly for your time.

I'm not a terribly accomplished shop tech, but I've done this succesfully more than once.

Hope this helps