Fitting new hammers to Rogers baby grand - advice needed!

[jamesp]

Evening all.
After a mamoth 7 week wait I now have a set of new hammers hung on new shanks for my Rogers baby grand piano. These were made by Abel in Germany. I have fitted all of the new parts now, and although I know that there is a lot of adjustments still to do I have noticed several problems which worry me - to this end I would greatly appreciate your collective advice.

Firstly, I am having problems with some of the hammers fouling on the metal frame. This happens for almost an octave of notes starting on the C above middle C. When the hammer rises it comes very close to the frame. I observed some of the old hammers and noticed that they had a millimetre or so shaved off the back face (nearest the keyboard) presumably this will need to be done to the new ones? I didnt want to just adjust the hammers further into the piano as I assumed this would result in an incorrect striking point.

Secondly (and rather more worryingly) I have noticed that a fair portion of the hammers have not been hung precisely perpendicular such that when the hammer rises it is not square to the strings, although I think the shank does rise in a perpendicular line. I assumed that they would get this right given that they had the old ones to copy? Am I expecting too much or have they done a sub-standard job? Would you recommend that I steam the heads loose and adjust them round, or should I reject them as not good enough? I really don't want to get into the whole steaming process since I paid a good amount to have these hammers pre-hung so I didn't have to deal with the complexity of hanging them myself.

On the plus side, it looks like they've got the striking lines correct; the hammers form a neat row when looking front to back.

As always, your assistance will be greatly appreciated.

Many thanks

James P.

P.S. This piano is turning out to be quite a journey for me - I think I may do a recording of it and put this together with a few piccies on the web for you all to see once it is completed.

[Barrie Heaton]

Shaving off felt on new hammers is normal. Have you tested the weight of the new hammers to the weight of the old ones? They will be heavier than the old ones so you may have to take of some felt from the shoulders to reduce the mass. #If the mass is a lot more than the old hammers you will have problems with your repetition springs and checking when playing soft. Hopefully Able matched them well.

When Able did your hammers they did them on a jig – the jig is not the same as your beam rail, you will have to do the casting and travel this is normal with new shanks and flanges. Don’t use steam use a casting lamp or cigarette lighter but don’t scorch the shanks

# You will need a very good set of scales that do 0.5g increments you have to take into account how many times the old hammers were refaced and the new shanks probably weigh more as well

Barrie,

[PianoGuy]

Evening all.


Firstly, I am having problems with some of the hammers fouling on the metal frame. This happens for almost an octave of notes starting on the C above middle C. When the hammer rises it comes very close to the frame. I observed some of the old hammers and noticed that they had a millimetre or so shaved off the back face (nearest the keyboard) presumably this will need to be done to the new ones? I didnt want to just adjust the hammers further into the piano as I assumed this would result in an incorrect striking point.

Whatever you do, don't shave off just the felt at the back. You must take an entire layer off uniformly over the surface of the hammer felt.

[jamesp]

Hi Barrie/PianoGuy. Many thanks for your responses.

Barrie: Yes, the new hammers are a fair portion heavier than the old ones as the felt pressing is much denser. Luckily on my action the repetition springs are adjustable with a screwdriver so I can fairly easily get them checking properly. I have had a go at casting a few hammers and this has worked ok. The problem I have now is that one or two notes are still sounding "stringy" and not as clear as their neighbours, even though (as far as I can tell) they are hitting the strings square on and in the correct place. Will these just play in or have I got something wrong. I assume the latter since other notes are playing clearly.


PianoGuy: I'm worried about taking off a whole layer of felt; why shouldn't you only take off at the back - the old ones were like this? (and therefore presumably wrong). I may be answering my own question here but I assume it is due to the tension in the felt being uneven? Assumedly that layer would not be held on both sides if one side is missing.

[PianoGuy]

PianoGuy: I'm worried about taking off a whole layer of felt; why shouldn't you only take off at the back - the old ones were like this? (and therefore presumably wrong). I may be answering my own question here but I assume it is due to the tension in the felt being uneven? Assumedly that layer would not be held on both sides if one side is missing.

Exactly right.

As hammers are pressed felt, the layer glued on to the core is under extreme compression, the outer surface under extreme tension (which gives it its bouncy resilience and longevity) and there's a neutral region somewhere in the middle. The close you get by refacing to the middle neutral layer, the flabbier the sound, but if you cut through a layer, that flabbiness is immediate, since the striking surface loses 90% of its tension.

Whoever cut the original hammers didn't understand hammer construction.

[Barrie Heaton]

Hi Barrie/PianoGuy. Many thanks for your responses.

Barrie: Yes, the new hammers are a fair portion heavier than the old ones as the felt pressing is much denser. Luckily on my action the repetition springs are adjustable with a screwdriver so I can fairly easily get them checking properly.

O’ boy your in for some fun - the hammers you have will be 15lbs that the smallest they do these days on grands , even when they recover they are about 12lbs – 13 lbs the small action HB did for baby grand’s were designed to work with 8 to 12lbs it’s the key, whippen, hammer ratio. Yes you can adjust the sprig tension with a screw but that is your problem. To work well the roller rests on the rep leaver with a 0.5mm gap (which is called carding) from the top of the rep leaver to the jack, so when the hammer is at rest the jack is not in contact with the roller, the rep leaver is held up by the spring you will have to set that spring at its limits and that will give you problems in the bass and when you are setting your blow. Then you have inertia problems that can be solved with more lead in the keys.

Myself I would take 2mm of each hammer 1mm on each shoulder a flat sander or belt sander but you must do it even and square. You will need a very good set of scales that do 0.5g increments. You can taper the tails to a V but don’t go wild.

Slicing felt off use a very sharp long knife 10” blade, place all the hammers in a long vice pointing upwards cut from 15 hammers further back the trick is to take off a layer in one long move it has to be done evenly, if you don’t they will be a bugger to voice later - if you have to old hammers practise on them first

I have had a go at casting a few hammers and this has worked ok. The problem I have now is that one or two notes are still sounding "stringy" and not as clear as their neighbours, even though (as far as I can tell) they are hitting the strings square on and in the correct place. Will these just play in or have I got something wrong. I assume the latter since other notes are playing clearly.

You have to take of the lugs and the hammers have to be voiced but you have a lot of work before that

Barrie,

[jamesp]

Hi all, thanks for your collective help. Hmm. Had I know at the start that it would have been so tricky I would have perhaps settled with just having the centre pins re-done on the old hammers.

I have found a highly recommended piano technician who is coming on wednesday to have a look over the piano, see how far I've got, and let me know how much it will take him to finish off the difficult bits. There was some mention of about £500 if he did the job to completion himself. I thought this was rather steep for about 1 days work?

[Barrie Heaton]

There is more than a Days work

Barrie,

[jamesp]

Indeed, thats what I thought; but he said that it if it were to take a day it would be £500. It remains to be seen. Fingers crossed for wednesday.