Upright action cycles

[Withindale]

Do you know if the inventors of upright actions intended the jacks to reset on the slightest release of the keys, enabling repetition, or only after the hammers reached the rest rail, preventing repetition?

In other words which of these cycles did they have in mind?

(a) Key pressed, hammers hits string and rebounds, back check catches hammer close to string, key partially released, jack moves under hammer butt, possible repetitions while key partially released, hammer returns to rest rail as key is fully released.

(b) Key pressed, hammers hits string and rebounds, back check catches hammer about 15 mm from string, key fully released, hammer returns to rest rail, jack resets ready for next key stroke.

(c) Both.

What are the advantages of (b), as described by Reblitz, over (a)?

An Answer
I have done some experimentation since I asked these questions, which are about the of performance upright pianos, mine and and maybe yours. What I found is that the touch and responsiveness improved greatly when I reduced the depth of touch, key dip. As a bonus the keys repeat like a grand, in so far as it is possible for them to do so.

The usual routine, (b) above, which Colin Nicholson mentions in the next post, will result in a key dip that is typically 0.50 mm to 1 mm greater than the alternative, (a) above; 11 mm or 11.25 mm compared to 10.25 mm to 10.75 mm on my piano. I much prefer 10.25 mm.

Though the depth of touch may be different, logic suggests similar results are are possible on any well made piano. It all depends on the movement of the jack. If key dip is great enough for the jack to escape plus a bit more, as is usual, it will not reset immediately. It will do so if the key dip is barely sufficient for the jack to escape or, indeed, about 0.25 mm less than that.

As I understand it, the big advantage of the usual type of regulation, is that it is stable. It is much more tolerant of changes due to use and swings in temperature and humidity.

On the other hand, your piano may play much better if you are prepared to make, or pay, for frequent minor adjustments to the capstans when lost motion develops.

[Colin Nicholson]

.... just tried to contact Christaforio
but he's not answering his phone!!

Joking aside...... b is the usual routine for an upright action.

It also depends on what you mean by "partially released" ?? how many millimeters has the key come back up??.... if just a fraction - say about 2mm, the key wont play the note, but if the piano is well - regulated and in good condition, I can get good repetition on my pianos after about 5mm of the key returning, hence:-

# jack springs in good working order
# notch leather in good condition & nap good (not grooved)
# jack tip smooth & coated in liquid graphite
# hammer butt springs working efficiently
# tiny amount of lost motion (back check winks before hammer)

If you want supa dupa repetition, then a grand action is better.

The advantages are obvious

[Withindale]

Hello Colin

Cristofiori referred me to Robert Wornum.

Fast forwarding to 1907, some people thought the back check was for quick repetition. J Cree Fischer wrote, "BC, is the back check which is simply a piece of wood with a thick piece of felt glued to the inner face and suspended on a wire.BCW, back check wire supporting the back check, and screwed to the wippen. The purpose of the back check is to check the hammer by coming in contact with the "back catch" (the backward projection of the butt), at a short distance from the string in its return, and prevent the hammer from falling entirely back to its rest position, thereby preventing quick repetition." The diagram is on Wikipedia.

Anyway, can we discuss this a bit further?

With close checking, which I set when reducing key dip on my piano, the keys will play the note when they have come up by 2 mm or more.

As the jack pretty much resets as soon as you start to release the key you have full control of the hammer throughout the cycle, except when it is on its way to the string and back.

I'd summarise the advantages of allowing the jack to reset immediately as reduced key dip, better control, repetition (including ability to repeat before dampers engage).

I must be missing something about the advantages of the jack resetting after the hammer reaches the rail. As an eminent judge once said things may be obvious but in his experience it was best to spell them out! I'd very much appreciate it if you would do that.

Many thanks.

Ian

[Colin Nicholson]

Ian

Shall we say that (in the nicest way possible).... some of your subject material, 'wording' of questions and assumptions are quite odd and possibly eccentric?, and dont readily give a concrete answer. I think the best advice would be for you to book a piano tuner, who will be able to go through the action cycle in detail with you.

I am sure that if your piano is well - regulated, you will see yourself the advantages and disadvantages if its not regulated. I also dont think your quotation in italics referring to the back check tells anyone anything!!!!.... I think all the tech guys on here (including myself) know what a back check is, and what it does. We also know what an upright piano action looks like, and all of the termonology that goes with it.

However...... dont let me stop anyone else answering these questions?

[Jonathan the 2nd]

As a newcomer I have edited my previous daft comment . I was having exactly the problems with repeating on an upright that were mentioned here. I think my problem is solved now.

[Withindale]

Hold your horses, Jonathan!

There is some very good advice in this forum, freely given. Colin answered my main question in his first and I hit the wrong buttons with an unnecessary supplementary.

Actually there is a closed forum for technicians, I understand.

So let's stick around without biting the hand that feeds us. There are all sorts of reasons why people have bad days. Not least when we ask daft questions!

Ian

[Withindale]

... some of your subject material, 'wording' of questions and assumptions are quite odd and possibly eccentric?, and dont readily give a concrete answer. I think the best advice would be for you to book a piano tuner, who will be able to go through the action cycle in detail with you....

However...... dont let me stop anyone else answering these questions?

Colin

My apologies for not taking the judge's advice and spelling things out clearly, and for wording them eccentrically.

What I might have said was something like this. The standard text today seems to be Reblitz; he says a repetition on a vertical is a full key stroke. When J Cree Fischer wrote his text a century ago, he spoke of quick repetition and checking the hammer a short distance from the string. I imagine this distance was much less than Reblitz's 5/8" and current manufacturer's standards (e.g. Kawai 15 mm, Petrof 18 mm).

When the tuner comes after Christmas, I will certainly talk to him about regulation. I will tell him that I was unhappy with the results of following Reblitz's formula, especially the 11 mm key dip. Andre Oorebeck's suggestions had helped to get it down to 10.6 mm. To do that I had to check the hammer close to the string; in consequence the jacks were resetting as soon as the key was released allowing quick repetition. The point I want to discuss with him is this; does the jack have to escape fully when it is going to retrace its path immediately afterwards? If not, the key dip could come down a bit more.

in case anyone cares to chip in, I really would appreciate any comments on this last point - how far the jack really needs to travel from the notch along the leather before the key touches the front cushion.

BTW all this kicked off when I asked Johnkie about jack slap rails on the American website. That created quite a stir. Many North American vertical pianos do not have slap rails, and in any case verticals and uprights can never repeat reliably, period. They work like Reblitz says and that's that, and why I was interested in the advantages of his method of regulation, basically the normal one in use today.

[Jonathan the 2nd]

Sorry Withindale . It came out worse than I meant. But is this the wrong forum for me as a beginning player and no knowledge of tuning at all? I feel as if I`m in the wrong place .

[Withindale]

Jonathan

This forum is great for specific advice on specific pianos, and no doubt more besides. The Pianoworld forums, if I can mention them, are broader in scope and have a huge archive. You may well find the answers to most of your questions, and many others there.

[Johnkie]

[/quote] Withindale BTW all this kicked off when I asked Johnkie about jack slap rails on the American website. That created quite a stir. Many North American vertical pianos do not have slap rails, and in any case verticals and uprights can never repeat reliably, period. They work like Reblitz says and that's that, and why I was interested in the advantages of his method of regulation, basically the normal one in use today.[/quote]


A good quality upright, properly regulated, and having jack slaprails can repeat reliably, period!!! The trouble is only well trained and experienced technicians are able to achieve the desired results. How on earth do you suppose grade 8 and diploma candidates are able to pass exams on upright pianos if their examination instrument can't repeat with reliability ? Yes there are those not fitted with jack slap rails, and as a consequence, fail to repeat reliably.

Just because a majority voice an opinion that repetition on an upright can never be made reliable (on another piano site), it doesn't make them right .... and it certainly seems that they have no intention of increasing their skills by listening to minorities. likewise, articles written in books aren't always to be taken at face value .... The skilled and experienced, rank far and away above the handbook tuner/technicians. As the saying goes " those that can... do .... those that can not .... teach !" and " a little knowledge can be a dangerous thing !"

[Withindale]

Johnkie

I trust everyone realises the points you quote are my summary of what our North American cousins said. You gave everyone a very clear explanation of how to adjust the slap rail, and one of the forum members who is responsible for pianos at a music school in London went off and tried it on a Blüthner and a Yamaha. I think others have learnt something, if only the existence and purpose of a jack slap rail.

By chance I came across Steingraeber's SFM magnetic repetition system yesterday, and the position of its jack slap rail caught my eye:



This may be a posed shot but as the rail is so close to the jack, one may suppose it's an important part of the SFM system. As it happens I think my piano is set up reset in a similar way, except with its springs, and when the workshop has made me a tool I'll try adjusting its slap rails.

May I add that Johnkie is absolutely right about a little knowledge being a dangerous thing when it comes to good quality pianos. The only way I have been able to get anywhere with my piano is by taking advice from experienced technicians on the forums. They have been remarkably open with their advice and, if I may say so, I'd commend every fine piano owner to employ their expertise.

[Jonathan the 2nd]

Does an improvement in that part of the piano relate to the advice I read for players that when playing a trill the fingers only need to release the key half way and then play the note again? That would give young players a chance .

[Johnkie]

Does an improvement in that part of the piano relate to the advice I read for players that when playing a trill the fingers only need to release the key half way and then play the note again? That would give young players a chance .

In my experience Jonathan that is exactly the point of things. Badly regulated jack slap rails make it very difficult, if not darn near impossible to trill with any certainty.

[Jonathan the 2nd]

Thankyou Johnkie. I wish I knew that when my children were learning. I could have made their lives much easier. I suppose one difficulty is that some pianos are designed a little differently .Some better than others too.

[Withindale]

Thank you one and all for your advice in this and other threads; it has helped enormously.

Depth of touch is down to 10.25 mm from the 11 mm that resulted from Reblitz's procedure. Amazing what a difference a fraction of a millimetre makes. The jacks don't escape, check distance is less than the norm, and the keys repeat at any depth but it feels fine.

Just as well, as the floor area available for Colin's supa dupa grand and its piano stool is 6' 6" x 5'.

[Withindale]

PS For general clarification, I have added an answer to the original question. This is at the bottom of the first post in this thread.

[Colin Nicholson]

Hi Withindale....

Have you measured the hammer blow?
This is the distance from the crown of the hammer (at rest) to the string.
One of the first 2 jobs I do is to set the key dip at 9.5mm (which is a standard key depth for uprights, but may vary slightly).... and the hammer blow at 47mm. Then adjust any lost motion, set off, back checks etc.

I think the general rule is a ratio of 1:5 - so starting with the key (ratio of 1) = 9.5mm.... then multiply that by 5 to get your hammer distance. It works out at 47.5mm - using some vernier calipers or a steel rule.

On older pianos when the jack starts to play up, or the hammer doesnt 'check' properly - then increase the key dip slightly.... maybe 10.5mm is excessive?
It also depends on the depth of the hammer grooves (if any) - so effectively, if they are deeply grooved - this will create a larger blow distance. Just use some card washers or a strip of felt placed between the hammer rest rail & baize to adjust the blow distance. If its say about 50mm and you decrease it to 47mm, you will then need to adjust the lost motion again.

Hope that helps....

[Withindale]

Hi Colin

Thank you. Actually I have measured the blow distance. Barrie and I went into it at some length in this thread Do pianists notice small changes in let off and aftertouch?.

Blow distance is at its maximum of 44 mm. With set off at 2 mm (bass 3 mm) the key travels 10.5 mm to move the hammer 42 mm, so the overall/average action ratio is almost exactly 4.0. I've heard the Schiedmayers liked to follow their own rules.

Those numbers bring your calculation out at 11 mm which is where I started; one suggestion on Pianoworld was 0.75 mm "aftertouch", 11.25 mm key dip - fair suggestion, hopeless result. I eventually settled on 10.75 mm, 10.5 mm plus 0.25 mm, and checking the hammer close to the strings.

After posting at the weekend it struck me there was no logical reason for the jack to escape, bobbling excepted; after all it was going back where it came from. Last night I popped in some 0.5 mm washers to bring key dip down to 10.25 mm, 10.5 mm minus 0.25 mm. That is about the limit. Checking is tight but it seems to stop any tendency to bobble.

Now it seem one key does not repeat as well as the rest. Is there no end to regulating a piano?

Ian

[Barrie Heaton]

After posting at the weekend it struck me there was no logical reason for the jack to escape, bobbling excepted; after all it was going back where it came from. Last night I popped in some 0.5 mm washers to bring key dip down to 10.25 mm, 10.5 mm minus 0.25 mm. That is about the limit. Checking is tight but it seems to stop any tendency to bobble.

Now it seem one key does not repeat as well as the rest. Is there no end to regulating a piano?

Ian

There are other factors that can make a hammer bobble look the jack slap rail there must be at least 1mm play when the hammer is in check - the other is the dampers lifting to soon making the damper wires touch the slap rail Again when the hammer is at its full cycle there must be 1mm play between the slap rail and the damper wire.

Barrie,

[Jonathan the 2nd]

See also J Cree Fischer .Piano tapes and stirrups. Closely connected with repetition . Grand pianos don`t need tapes for repetition .

[Withindale]

Grand pianos don`t need tapes for repetition .

Thanks to Newton.

[Jonathan the 2nd]

Perzactly . The tapes are supple and subtle .