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Greetings from Finland from a new forum user!

I recently got a 1918 Blüthner Style VII grand piano with Blüthner patent action for very cheap. It was in neglected shape, but it is slowly becoming playable again. One of the issues is that there is some slack in the una corda mechanism. There is no adjustment mechanism of any kind for the una corda pedal or rods, and the slack is quite noticeable.

The una corda lever is directly pushing the wood at the bottom of the action, and I suspect there should be some part there that's missing (there were other parts missing as well, like lyre support rod, some hinges and screws etc). A missing part would explain the slack.

The piano technician who has done some of the repairs for the piano suspects the same, but she is not that familiar with Blüthner patent action. In some grand pianos there is a brass plate attached to the bottom of the action at the point where the una corda lever pushes it. Should there be something like that in the Blüthner patent action as well? There are some holes that might be mounting holes for something, but I think they are not screw holes as they are not circular.

I've tried to ask this question directly from Blüthner, but received no answer.

Does anyone here have access to a Blüthner patent action and could take a look? (Or even better, take a photo!)

Below is an image of the slot for the una corda lever at the bottom of this action. There is some wear from the lever pushing directly at the wood, but considering much worse level of wear of the una corda pedal itself, I think there might have been something protecting the wood earlier.

A google search for "what is bluthner patent action" turns up potentially useful results for you.

Invincing, your link to the picture does not work. Try this procedure:

http://forums.pianoworld.com/ubbthr...o-post-pictures-video-demonstration.html

It might help to know where you are located.

Hello there!

Lack of adjustment on the old Blüthner grands is rather annoying...

The photo you posted looks to be correct; there was never any metalwork on the Patent action shifter slot.

Have a look at the pad on the shifter arm; it might just be a case of fitting a new piece of felt there.

Also, look at the top of the rods that connect the pedal to the mechanism; there should be a gap under the Steel mushroom on the top of the Brass rod (about 2-3mm; it should not be resting on the lyre top). If there's no gap, then the pad inside the pedal box on the lyre probably needs to be built up, which should be possible by pushing a shim under the pad which will be a piece of cloth nailed over a couple of pads if everything is original, or just glue on a piece of felt. Oh, and while you're in there, check for wear on the felt pad on the back of the pedal and replace if necessary!

With all those felt parts replaced, you might be able to avoid doing anything to the slot at all!

If replacing the felt doesn't do the trick, then you'll need to clean the side of the cutout, then add a piece of Beech to build up the side of the hole. It's possible to do this without dismantling the action, but can be a bit tricky. Adjustment is then done by paring away small pieces of the new wood until the action rests against the runner on the left side of the keybed. Be careful not to take too much off in one go.

PM me or contact through my website if you need any more details; I've still not figured out how to post photos on the forum from m' Mac...!

Thanks Adypiano for the detailed explanation!

Below is an image of the una corda lever that pushes the action. So should there be some padding on the lever? On the other end of the lever there's a round leather padding (the lyre rod is pushing on that padding), but here it's just iron directly pushing the wood.



BTW I figured out what's wrong with the image in the original post - if you browse the forum with https, it works, if you browse with http, it doesn't. The image was embedded with https URL, so if I'll try with just plain http in this post, let's see if it works better...

Here's also the first image embedded with plain http URL:

That looks fine; there shouldn’t be any felt on the shifter arm there, just metal against wood, with a bit of wax on the wood to prevent squeaks.

The felt pad will be at the other end of that arm where it meets the rod connecting the pedal. They often compress/wear, or even get knocked off during transit.

Ok, then it must just be the padding at the other end of the arm being too compressed. It's leather, not felt, but it's not necessarily original. The bottom of the "mushroom" is few mm above the lyre top, so the position of the rod should be correct.

Thanks for the help!