Hi all,
I have begun working on a project piano with overly tight hammer flanges.
The piano is a Baldwin Acrosonic from 1965 that I picked up for free. Flanges were causing very slow, creeping, hammer return.
I'm half way through repining. Hammers are now swinging between 6.023 and 9.278 times. Approximately.

RXD's signature portrays him as a "Recovering Perfectionist."
I am thinking about changing mine to "Hopelessly Hurtling Towards Perfectionism."

So, I'm curious. I imagine it's rare that any of you do this kind of work on a piano like this, but, if you WERE gonna do it, what would your tolerances be? How tight would those tolerances be under different conditions.

Thanks

Three swings in the winter or two swings in the summer is about as close as I try to get. (Are you sure you aren't getting 6.024 swings?)

9 swings sounds like a lot to me. I always try for 4 to 7 swings. Keep in mind the heavier bass hammers will swing more than the lighter treble, so ideally you would have 7 swings in the bass tapering to 4 swings in the treble.

If you really want to be more of a perfectionist use a gram gauge.

Also keep in mind that swings can be deceptive. You can have a tight center one side of the flange and a loose center on the other side and get correct swings, yet the flange will not be stable.

David is correct that the relative humidity of your workspace should have some bearing on how tight you pin the parts. If you are in a 70% RH environment you will want to pin significantly tighter than if you are in a 20% RH environment.

Good luck with your pinning project!

I was trained to re-centre hammers so that they swung 2.5 times. Anything over that ... and my foreman did his nut!

After broaching the bushings I always lubricate the centre-pin before inserting it, and then check the resistance is correct. Lubricating the pin allows less friction to be obtained and therefore a firmer overall re-centering job. If lubrication is not applied, the bushing has to be broached out more to obtain the 2.5 swings, and as a result, the centre becomes less firm.

We used to use natural tallow ( the slightest smear, otherwise the centre became clogged over time ) - but these days, dipping the centre-pin in Protek works a treat without causing any danger of over-doing it.

Hammer centres are the most important to get correct, where as the others can comfortably get by with being a tad more on the loose side of things.

You want to make sure that the centers move freely and evenly, but firm. Your swing numbers sound like a lot. When I've done repining in the past, I've used the swing test in conjunction with a gram gauge. I've never done uprights, but for grands, the tolerance was to keep it between 2-4 grams (and if the flange was loose enough to flop around from its own weight, it was too loose).

I like a go/no-go type of tolerance. I want the flange, when horizontal, to hold a penny but not a nickle.

Be careful that the friction is about the same on both bushings. You can tell by resistance in putting a pin in each side of the bushing. For that matter you can tell when it is broached/burnished about right from the resistance in putting in a pin.

When Ryan describes the swings, he means, half swings, not full swings. Which is about, roughly, 2 to 3.5 full swings.

Yea. 'Excellent point. 'Funny how you get used to thinking half swings and write "swings" as though everyone else is on the same page.

Monaco,
Did you try Protek on the flange bushings first? I have seen a number of older Baldwins with tight hammer flanges, especially ones that were not played too much. Often Protek will make them work properly. If that doesn't work, then repinning is the answer.

ARGH!
I was counting half swings. Even so some of my flanges are still a bit loser than what was suggested here, especially since it is a tad humid here (55%).
Now for the practical part of this question. In this old, cheap project piano that I got mainly as a learning experience for myself, is it worth redoing? My eventual goal is to get practice a full regulation on this piano before I graduate to my Kawai US-75. With this Baldwin, I plan to either continue with the rest of the flanges using the same method, or redo all of them. Any way to tighten them up without repining?

I did not try protek for a couple of reasons. One is that I wanted the learning experience. Two is that I have heard mixed things about using lube. I believe it would be less consistent than repining and probably not last as long. If this was a customer's 50 year old spinet, I would probably recommend that as an option. Either that or a bonfire.

Learn to get the feel for the resistance when reaming. After a while you can learn to gauge yourself better at how much to go, both for reaming and for selection of pin size. Check for bent pins and always check that the pointy end gets inserted. I blow out the hole real good to remove bushing residue. For lube, I just run the pin through my hair before inserting...they did this in the factories since the turn of the last century and the oils in your hair works really well for this.

Yes! Until you learn to do it right, you haven't learned to do it. I think you know this or you wouldn't ask. Hey, it will go a lot easier the second time around.

That's great if you have hair

Les, you can always head south if there's a tundra in the north.

I went back and recounted swings.
I only have 9 hammers with 7 or more (half) swings, so I will repin those. I did find a few that had less than 6 swings. I wonder, did things tighten up a little? Maybe humidity. It was raining yesterday. Also wondering, does "working the flange" have a long term effect or does it only effect the bushing while the heat from the friction is still in the system?

Ben:

Counting swings can drive you crazy. That's why I use a penny and a nickle. Friction in parts do change.

Thanks for the advice Jeff, but I have a question.
Obviously, using a penny or a nickel doesn't eliminate changes in friction so I can only assume that you mean that it is a more accurate way of measuring the friction. Is this correct?

Thanks for that, Jer! You're right, what I think of as swings are really half swings, so Johnkie's foreman was right!

I like the penny/nickle go/no go gauge idea.

I'm not quite so sure about using anything other than the "feel" of the centre pin in each side of the flange before inserting the pin though. The reason being, that one can be mislead easily that the centre is correct, when in fact one bushing may well be too tight and the other too lose, but still give the impression that all is well. In which case the the hammer swing would indicate a good job, when in fact the hammer would tend to wander from what should be a constant trajectory.

I too also pass the centre pin through my hair as a means of applying lubricant ... providing I haven't just washed it ! Protek works a treat though if your hair is too clean, or not enough of it:)

So that's why piano technicians always have greasy hair!

Dump a few bottles of Protek CLP over the entire action.

Spray 'em with WD-40! ... NO DON'T!!! I'm kidding.

(Only use WD-40 if no one is looking.)

Since the #1 hammer weighs more than the #88 hammer, yes, using something other than swings will measure the static friction more accurately. I have read debates about the how counting swings is better because heavier hammers should be pinned tighter. So it is open to debate which is "better" aside from more "accurate."

I just think that the penny/nickle test is more practical because it is a go/no go gauge. As you have already found out, the friction changes...

I'm happy with the case for coins but, for my edification, why should heavier hammers be pinned tighter? More shock to absorb when the hammer hits the string?

Ian:

Well, if for no other reason you need to have heavier hammers pinned tighter so you have the same number of swings!

I think the tighter the better as long as the action is not sluggish. I think it makes for more consistent touch and tone and longer action center life.

As long as we're on the subject, I will be repining the whippen flanges on my Kawai later. What do you shoot for with those?

Whippen flanges? Same thing, I guess. Between a penny and a nickle. I suppose damper flanges could be tighter and jack flanges should be on the loose side. I'm not a rebuilder... Maybe someone else can give better guidance. There are gram scales available for this sort of thing, too.

Whippen flanges are pinned so that they fall on their own weight which is what they do in motion anyways. Once the capstan is removed (key going up) the whippen is subject to gravitational pull.

Jeff, just where do you put the penny and nickel for your testing, and what part are you testing with it? I've done the hammer swing test and I've even used the mounting screws in their hole as a go/ no go test. I look for about 1 swing on a wippen when the actions held in a cradle, any less its probably too tight. I do use a dime on the drop screw pad to test the rep lever with the spring disconnected. Lately I rely on my 40 year old gram guage tool for individual removed parts. I can't see how you could position a coin accurately on a flange to get a good reading...a screw will sit nicely in the hole.