Facilitating rebuttal

...sink 10mm. Try pulling the straps and check the hammer return springs. check that the escapement is not more than 12-15 mm from the string

I checked the movements more closely and noticed that the repetitions tend to gradually rise towards the end of the escapement instead of returning underneath, and therefore the hammer tends to recoil

I have the check as close as possible; I tried to set it a bit closer, but it ends up that in pianissimo, the hammer remains "pressed" against the string, so I would say it's OK

But by tightening the springs more, do I facilitate the return of the repetition lever into its seat?

Additionally, my piano has a repetition return system via a spring... Could this last one be worn out?

No. You must, then, check the hammers. The hammers must rest on the rest felt and the shank must be able to position itself freely and easily under the cap almost without play, easily. Stimulating the shank with a wire, it must return under the cap without friction. The regulation, from what you are telling me, seems to be too far forward

The pilots are okay, there is no play under the finger when I touch the key, but the lever still manages to get under the knuckle easily

The problem only manifests if I try to restrike the notes quickly, i.e., with the key halfway down

So could the problem depend on the hammer parameters?

consider that you are playing an upright piano. The performance you are requesting can be given to you by a repetition lever, don't you think?

Of course, I understand that it doesn't have "double escapement," but it seems strange to me that the repetition lever continues to rise...

I was anyway making various attempts on some notes and I tried to bend the repetition spring and I must say that the problem seems to be resolved

I don't know if the image is visible, I am having problems with the upload

If the lever continues to rise, there is too much key dip

What size should the aftertouch be?

That is, by how much must the hammer retreat after striking the string?

Additionally, I have a curiosity...

If after "escaping", the hammer returns and upon releasing the key, the hammer advances a few millimeters forward before coming to rest, is that a sign of good regulation?

And anyway, the mechanism I was referring to is this one, but without spring and cord adjustment screws https://youtu.be/UOV6Khfk4cg?feature=shared

Gib wrote:

On 11/03/2025 at 13:24, Gib said:

I was making various attempts on some notes anyway and I tried to bend the upright's return spring and I must say that the problem seems to be resolved

Open content (youtube)

you cannot explain everything from a distance. The aftertouch also takes into account the depth and the hammer-string distance. Generally, it is about one millimeter. The video you posted refers to an attempt made on some pianos (e.g., Schimmel) to simulate a sort of vertical repetition. One should ask why many manufacturers have not embraced the idea.

I understand, with the aftertouch we are there anyway

I was wondering how to best adjust this action since with the weak spring it's like not having one; if I tighten it a bit more, the repetition works great, the hammer still manages to escape but when playing pp sometimes the hammer hits the string twice

Anyway, it is a Langer action from the '30s

check the hammer grip (if the depth is correct!)

From the point of view of wear and tear?

Or if I have to bring it closer or move it further away?

The inclination

Thanks, I will try it that way

Also because it only happens on some notes

This Langer mechanism is interesting, but be careful not to overdo the spring tension so as not to compromise control in pianissimos. Perhaps a compromise between tension and escapement regulation could help you maintain the repetition without the double strikes you are currently hearing.