I am trying to get good, consistent numbers for downweight, with a once or twice tap to the action to start the hammer moving in a slow, even, up motion. Looking for a DW between 52 & 48g.

But it's not happening.

Some of the hammers begin to move without any tap to the action (way too little friction), a few move as they should; but for most, I tap, the hammer moves a 16th”, I tap again, it moves another 16th. I keep doing this (wearing out my hand) until the hammer finally reaches let-off (doesn't go through it).

Of course, I can put on enough weight to overcome this start-stop, but, when I reach that much weight, about 70g (a bit much), the start-stop hammers move up quickly, without any taps.

What I want is to put a 50g weight on the key, give the action a tap, and the hammer glides slowly up.

I've been shooting in the dark, to fix this, with no success.

Here's what I've done:
checked the FR & BR key pins for causing the key to stick in the bushings or balance hole: eased and/or reamed as needed
dry maclubed the FR & BR pins
replaced the capstans with highly smooth ones
checked the wippen bottom felt for smoothness
replaced the knuckles—with nap going the way Renner specifies.
rubbed powdered teflon into the knuckles
checked hammer shank pins for tightness—most are too loose (8 - 10 swings)
put the jack through let-off, many times, to get it moving smoothly over the knuckle.

Something is hanging up the hammers. If I can find the answer to one, it'll probably be the same for all.

I need ideas for a systematic way to determine what's wrong and a fix.

Thanks,
Bob T

Additional things to try:
* Make certain that the knuckle from one key is not rubbing on the knuckle of the neighboring key.
* Make certain that you do not have hammers rubbing against each other.
* Make certain that key sticks are not touching each other.
* Make certain that the felt on the back of the key sticks that the damper underlevers sit on are not rubbing against each other. (What's the proper name for that piece of felt?)
* Remove the stack. Apply enough weight to the back of a keystick to make it balance. Now see how much weight needs to be added to either side to make that side go down. It's been a while since I did this, but if I remember, it should be in the 3-4 gram area. If too much, you may still have balance rail or front rail bushing problems or other key stick problems such as key sticks rubbing together.
* Make certain your whippens are not rubbing against each other.
* Check your whippen flanges. I think they are supposed to be at 3 or 4 grams. Someone else check me on this, because I'm not real certain about the proper friction for these.
* I assume you're aware that the damper pedal should be blocked such that the dampers are all up. If not, maybe you have dampers rubbing against each other. Well - moot point for the moment. Make sure the dampers are up. But if they are rubbing, then you need to eventually fix that anyway.

Thanks Jerry. I had checked for rubbing of anything, but all is in the clear. The jacks are centered, also.

The action is out of the piano, so there's no problem with dampers. I'll check the balance of the keys--right now though, there is no lead in them since I'm touchweighting.
It's really hard to touchweight when it's so hard to get a good, downweight, without tapping and tapping and tapping.
I checked the wippen flanges with my gram gauge--that was okay, but I don't know how to tell if it is moving smoothly on its pin.
Obviously, the hammers are not sticking since they are so loose.
My thoughts are it must be something with the knuckle, top of jack being rough (but it doesn't look or feel like it), the jack flange, wippen flange.
I even went through one wippen, completely repined it, setting all the flanges to the correct g. But that didn't fix it.
Since the hammer flanges are free, that means the jacks are starting then stopping on their knuckle, but what can be causing that, which I haven't already checked?
I am totally frustrated. I know though, once the problem is found it'll be a simple fix--it's just how do I find the problem?
And then there are a few keys that works perfectly: set my weight at the front of the key, tap the action, and with the right weight, the hammer glides slowly up.
It's very frustrating to have to tap, sometimes quite hard, the action 12x to get the hammer to "glide" to its let off.

Try lifting the hammer up off of the whippen. Add enough weight to the top of the rep lever to simulate the weight of the hammer on the rep lever. Now see if you have to tap-tap-tap. If no, then the problem is somewhere in the knuckle//jack interface or other part of the hammer. If yes, then the problem is in the whippens or below.

One other thought - Have you adjusted the rep lever heights? Not sure if a misadjustment here could cause your problem. But something to think about.

Please tell me this is'nt your fairly new Estonia you're messing around with.

Did you set rep lever height, spring tension and jack knuckle alignment?
Have you measured any up-weights? Total friction is down minus up divide two. Should be 12 grams +/- 2g range and even.
You should work on technique for using gram weights. Put them on the key in exactly the same location, one light tap should be all that is needed to break friction - do it exactly the same all the time. Release weights that hold key down and key should come to up to full rest for up-weight.
Use the technique on all keys and record.
Zero in on the ones that have high friction and recheck touchweight to see if it improves.

Am I reading this right? You have removed all of the lead from the keys? And you are "touchweighting?"

Just what do you mean by "touchweighting?"

If all of the leads have been removed from the keys it would not be unusual to find keys in the bass requiring 70 grams of weight to push them down.

ddf

lots of good ideas for me to check. thanks guys.

Yes, Delwin, what I meant by the 70g comment (that may be exaggerated a bit) is while trying to get a reading for the DW, I can put around 50g on the key. Give the action a tap, the hammer moves slightly, tap again and again and finally the hammer gets to let off. At 49g no matter how much I tap, the hammer won't move, so I suppose the DW is close to 50g. But, if I keep adding weight, there comes a point where just touching the action will cause the hammer to take off, very quickly or it will take off on its own. This occurs at about 70g, which is ridiculous. But it shows pretty well that something(s) is causing the hammer to hang and do the start/stop thing. My UW comes in at about 25g, so that's consistent with a DW of 50g. No tapping is needed to get a good reading for UW.

One thing I notice is that with tapping at the 50g, once the hammer gets to let off, when I gently lift the key back to its up position, let go, give the action a tap, it glides down as wanted. But, if I let it stay in its up position for a couple of seconds, it's gone back to the tap, tap, tap, problem. Does that give any more ideas?

And Curry, sorry, I have to tell you this IS my Estonia. But it needs it.
And I'm not stupid enough to try this by myself. Once this is done, this Estonia will go from being a very, very good piano to a great piano. What we are shooting for are to get its touch close to a Hamburg Steinway.

In my area there are two of the best techs in the country. One is helping me, with every step. He is a registered Stanwood tech. He also gives classes at the PTG conventions, most recently in Vegas. So, I'm not doing this by myself. I wait for his guidance on all the touchweighting.

When he isn't available, I can do things like trying to track down this start/stop friction problem. Although no success yet.

(btw) I'm probably going to have to repin all the hammer shanks. There are many that have loosened and can be pushed back in with a finger. But, I've played the piano heavily and it makes sense to have the pins loosen, especially after the work out I've given it.

Bob

Oh, Delwin, I forgot to mention. Although the lead is out of the keys, there are leads positioned on the top of the keys, but re-positioned towards the BR pin (instead of being heavily weighted at the front of the key) that will balance the g weight placed at the front of the key to get the DW/UW.
With the tap,tap,tap method--the DW is coming in between 52 & 48g, with friction around 10 or 11. I just have to find out why the hammer only moves a little with a tap and requires many taps to get it to let off.

bob

Perhaps I’m just reading your earlier posts wrong but it sounds to me like you’re doing this with all of the factory-installed keyleads removed from the keys. Is this correct?

ddf

Sorry, I've been unable to be back on the computer 'till now.

That's right. The each keys had its weight in the front, which is okay for slow to moderate playing but not for fast playing, so they were removed, to reposition them towards the balance rail.

In re-leading, a consistent balance weight was shot for (35g). The leads were repositioned close to the balance rail to get that BW ((DW+UW)/2).

With that done, the keys were weighed-off to get their front weights. Using those numbers as a guide, changes were made to make a smooth, descending FW curve.

With the new numbers, proper number and amount of leads were placed close to the BR to achieve the new curve. Holes were drilled and the new leads installed. Wippen assist springs used to even out the DW 50 - 46g, going from key 1 to 88.

The keys now have a consistent balance weight and graduated DW/UW, with the leads towards the BR, versus being in the front of the keys. -I still need to even out my friction, but that won't change the BW.

I still have the original problem though: in measuring DW, with weight placed at the front of the key, I tap to get the key moving down--the tap should break the inertia of the key being still and it should then glide slowly down, as the hammer moves slowly up to let-off.

Instead, the tap starts the hammer to move, but the hammer almost immediately stops. Another tap gets the hammer to move again. I can continue this until it gets to let off. I use the amount of weight to accomplish this as the DW.

If I don't put enough weight on, I can tap all day and the hammer will not move. If I go to the other extreme and put too much weight on, the hammer moves quickly to let-off, without any tap.

What I want is between the two. One or two taps, starts the hammer gliding slowly to let-off, without the start/stop.

I can't determine what's causing the hammer to hang.

I checked for rubbing parts, lubed all friction points, checked for proper Jack allignment to knuckle, checked the top of the captstans for smoothness. Checked the top of the jack for smoothness. Lubricated, with teflon, the new knuckles. Made certain the top of the capstans are smooth.

Nothing seems to correct the problem & it happens with almost all of the keys.

Whatever is causing the keys to start and then stop is probably same thing doing it to all of them. I've also checked the keys for hanging on the BR pin.

I'm at a loss as to what next to look at. It's really frustrating to not be able to find the problem. It's obviously a friction problem, but what is it?

Bob

Possible solution: Remove/unhook the whippen assist springs leave them out of the equation for the moment and re-weight.....

Might be key bushing damage. The bushing has wear/cupped imprint and requires replacement.

How is the magic line ? how does the key botyoms ? is it level when bottoming or at half blow

When porperly set some action will need 1g more to raise a little, then another, then another, because the ratio raise a little before lowering.

it is a joke if you expect a Steinway action touch, or you have different references than me.

Also, playing with key inertia makes a too little difference,while lowering the key stiffness too much to be someyhing I would do (I have seen samples of that)

-I still need to even out my friction, but that won't change the BW.
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If - as you state (DW+UW)/2)=BW then friction will change BW as the friction changes. Friction = (DW-UW)/2).
Repositioning key leads is done after friction issues are addressed.
Your posted numbers show friction in the range of 15g bass to 12g treble. On the high side but not outrageous.
When doing action balance most of the friction issues should be solved first: New or refirbished parts should have had flanges and other pinning checked prior to assembly. With whippens out, check rep spring seats. Parts assembly takes care of knuckle/rep lever alignment. If you align hammers to strings then knuckle/rep lever needs to be aligned again.
All keys should be eased as required.
The action regulation should be close - at least a first or second pass.
Damper lift lever tray should be proped up so the dampers are out of the equation.
I agree with Dan, measure touchweight without the helper springs.

Agreed with Isaac on the key inertia. You could measure your key inertia but that is not where the problem exists here.

For inertia measurement if you have a inertia balance set up (Mark Davidson 1/10/2004) you could do some measuring. If not, it is relatively easy to perform the penny drop/ click test.

A typical key with leads will be in the 20-30kg∙cm² range......

problem with older Estonia was a too tall strings plane, by a lot. I dont know what are the actual mesures but above 198 mm forget about velocity, the action is then too tall (Steinway = 190 mm and less in the treble)

Here's a shot in the dark, if nothing else maybe it will get someone looking in a new direction: Are the hammer tails clearing the backchecks completely?

String s plane height : in fact if the hammers are more than 48 mm they begin to be less direct.
Modern setup is in the 192 198 mm range.

Above that the key frame may be thicker than usual.