Hi Olek! Thanks a lot for your dedication!
I would like to change the hammers, but I have no idea how to get them. How much do you pay for a set of new hammers? I don't think the piano owner will like this idea...She really would like buying a new piano instead.

I will measure hammers angle nex time.
Knuckle to center pin is 18mm, measured on shank axis line, from middle of center pin, to middle point of knuckle wood core.

Now you give me lot of new ideas. But I suppose that first I must try to enlarge spread by moving the wippen rail, is that ok?
I already raise the back cloth and balance punchings, to get standard key dimensions. Is it posible to directly raise the back of the key frame in a case like this?

Thanks!!!
(Now, I go of camping for a few days)

Hello, Hammers are not that expensive but if you are not used to change hammers you will be in trouble, particularly on an old piano where they where light probably.

If the jacks are well under the knuckle you probably do not need to change the spread, you will need more key dip if you do so. Changing stack height and orientation can help, but can be time consuming, very probably the touch will feel better as soon the hammers impact correctly the strings (even if it is not ideal the tone advantage may suffice to give a better sensation in the end)

Hello!

I HAVE GOOD NEWS!!

Changing stack height and orientation seemed to be a very complex work to me.
So I'tried enlarging spread about 2mm, obtaining incredible results! No more problems regulating let off and hammer drop!!
Now I need to increase key deep, mainly on blacks, because there is not enough hammer travel and aftertouch. But this was also needed before changing spread.
How much aftertouch is the ideal measure?
Is there any way or any tool for home making paper punchings for keyboard regulations? (remember: I live in Patagonia Argentina...)

Aftertouch should be about the thickness of a moderately thick coin. 1 to 1.5 mm.

You might be able to find punches for making the punchings. There are plier-type punches that could make the center hole which you might find at a fabric shop or hardware store. If there is a supplier for leatherworker's tools, you might find them there. You need punches about 22 and 4 mm for the front rail punchings, 12 and 3 mm for the balance rail.

Aftertouch: Measured at key travel?

Punchings: So, I first make the inner hole, an then I cut the external circle with scissors?

Thanks, BDB!

Aftertouch: Yes, you can put in a piece of cardboard about that thickness and adjust it so the hammer just lets off, and then a piece of stiff paper to make sure it no longer lets off to set it properly. If they are long narrow strips with a slot that fits around the front rail pins, you can slip them in and out while you test notes in several registers.

Punchings: You can do that. They do not need to be perfectly round, but they should not interfere with the next note even if they rotate on the pins.

OK. I understand! Thanks!

I am a bit puzzled. From your questions, it is clear that you have a very limited knowledge and experience regulating grand pianos. I am sure I am not the only one who thought you were simply someone working on their own piano because there was no technician where you live. But gradually I get the feeling that you are the technician.

While I wish you luck in your endeavor, you must understand that you really need to educate yourself in the field of piano technology before you take on this kind of work on other people's instruments. I think it is a question of ethics, personally.

Here's another suggestion: if the owner wants to buy a new piano, she should buy a new piano. This one looks nice, but it's at a minimum 90 years old, and she doesn't want to go for new hammers.

Maybe you should buy the piano from her and install new hammers, learn a lot in the process, and then you'll have a piano to sell.