Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum OK, so now what??

As anyone who has noticed my signature knows, part of what I do is help DIY-ers work on their pianos. This is as legitimate as someone doing their own electrical, plumbing or restoring an antique automobile. Many people are able to do good work if they are pointed in the right direction but this kind of project is also fraught with the same kinds of opportunities for something to go wrong. A big part of my job is to keep people from making mistakes.

The worst offenders seem to be accomplished shade-tree mechanics and professional engineers. Either way, they are convinced they understand what needs to be done and proceed with a confidence that can turn out to be unfounded. Anyway, with that as background . . .

Someone who is restoring their piano and is planning to install new hammers (on the old shanks) has completely removed every single one of their hammers and disposed of them. That's right, no guide hammers, no factory jig, no pattern, no measurements, no nothing except bare naked shanks and a set of unbored, un-tapered, un-tailed hammers with moldings that are therefore nothing like what was originally there.

Getting the new hammers close is easy. But accurately reproducing the strike line is more of a challenge. I don't think it's a lost cause and I have some thoughts, but I thought I'd see what kind of approaches people here might suggest beyond the obvious but too late "you shouldn't have done that".

Have at it . . .

If the strings are old enough, you might find some shiny wear spot where it struck as a starting point. I see some serious experimenting in your future. Obviously if this is not a rare/old piano, try and find one similar to model off of or contact the manufacturer if they are still in operation.

Otherwise, take any extra hammers and drill right through them slightly oversize and use hot glue to temporarily shift it around in different positions. Most importantly, charge accordingly. Rewarding somebody for this type of nonsense does nobody any good.

I don't bore hammers, so take this for what it's worth...

It should be fairly easy to determine where the strike point for note #88 is, as this is a very narrow window on all pianos.

If the original bass strings are on, might they have a mark where the hammers were striking? If so, that could be a start to figure what strike ratio the original strike point was on note #1. With these two points, you could interpolate the strike line for the rest of the piano.

Bore distance is easy enough to calculate based on the existing strings and action rail. The key would be whether the DIY'er can come up with accurate enough measurements to be useful, though, we all struggle with that at times.

As I've said, though, I don't bore hammers, or hang them much, really, so this may be way off in left field. Would the WN&G scale stick instructions be applicable here?

Regards,

Now that I think of it, is it a grand or vertical piano?

It might be possible to take measurements from another piano of the same brand and model. This could at least be a starting point.

You could then try gluing sample hammers at the ends of each section and see how things work out.

Edit: Another possibility would be to try contacting the manufacturer for the specifications, if they are still in business. The worse thing that could happen is that they tell you they no longer have that information.

I hope you are within driving distance.

Good luck
-Joe

Upright pianos are not too difficult. I make a pattern of note 88, starting with the string. This usually has a length of about 2", but I only need enough of it from the top of the speaking length so that I can strike a good perpendicular line, which will be the center line of the hammer. This perpendicular will be about 1/4" into the speaking length, which is about 1/8 of the total speaking length. The critical measurement is from the plane of the strings to the position of the center pin of the hammer butt flange. Once you have this, and choose a bore distance, everything follows.

Place a butt on the pattern so the center pin joint is at the position noted. Put a hammershank in it, and pivot the butt until the hammershank crosses the perpendicular at the chosen bore distance. This gives the angle at which the hammers should be bored, as well as the length of the shank. Bore the rest of the tenor hammers to match. Then you will have the strike point for the tenor strings. Decrease the bore distance for the bass hammers by the amount the bass strings are above the tenor strings at the break at the line of the strike point.

Afterwards, you can determine where the hammer rail needs to be.

You can adapt the same method for grands, working from the plane of the strings and the center pin of the shanks, but it is much more difficult. The access is not as good. There is not so much tolerance for the bore distance, as it will affect the drop and other functions of the action. You have to make sure the back of the hammer does not hit the belly rail. You should aim for the hammers to be bored so the shanks are parallel to the strings, which should help a bit.

Without a lot of experience doing this with grands, I would aim less for precision, instead aiming to make sure that everything works. Bore the hammers a little straighter, so that they are closer to parallel to the shanks, rather than the strings, particularly in the bass. That will make very little difference in how the piano sounds, and it will make it much easier to get the hammers to fit in.

Also, you can move the action slightly for a better strike line, although this is also more difficult with grands than with vertical pianos.

Remember, even the manufacturers were not always perfect!

The treble is where a couple of millimeters is the difference between "life and death" in tone. I have used the following ratios for good effect for a number of years:
Note 88-1/17th
83-1/15th
78-1/13th
73-1/11th
68-1/10th
63-1/9th

Measure the speaking length and multiply by the ratio and that is the distance the center line of the hammer should be from the V-bar or agraffe hole. Since the shanks are still there that gives you enough information to hit the mark in the rest of the scale granted you determine the bore distance and any rake angle. BDB's method for finding rake and bore sounds excellent. The angles for the string fan can be recovered from a paper pattern made over the V-bar and strings with the strike line indicated to within 2 mm.

I have a rather dim view of do-it-yourself piano work. Do they want to PLAY the piano or WORK on the piano! I have seen some engineers who handle most of the elements quite well though. Woodworking skills are usually a little weak-but then again they are in the Tech community as well.

thanks for the replies so far.

It is a grand and all the strings have been removed.

It's an old Hardman. No info available.

He removed the strings, too?! I assume he didn't measure. Did he at least save samples from the bass strings or take measurements there?

Your signature says: "Supporting Piano Owners D-I-Y piano tuning and repair." It doesn't say D-I-Y rebuilding. It seems that he is dragging you well outside your advertised scope.

I don't like to criticize people, but this guy does seem a tad bit reckless.

The important thing is to stop him before he does anything more. This is a bigger problem than the missing hammers. Even if you can teach him how to rebuild, what if he starts subverting you?

I would advise him to either ship the piano to you for rebuilding, or to someone you refer him to.

He has missed his chance to do the job. It's time for him to let someone else take over.

Edit: I'm sorry, I don't mean to offend. But, this is how I see it.

I think this story could serve as an example for the many over-anxious, well-meaning but ignorant (in the best sense of the word) folk out there who want to rebuild their piano.

Years ago I complained to one parts supplier about the custom bored hammers I was receiving - there were only 88 hammers in the package - none for spares or replacement, if one should fall into the glue pot etc.

I was told that in the past, they had bored and shipped all the hammers (94 in a set) to clients. Then the complaints started to come in: "The bore angles in the low tenor are way off!" It turns out the DIYers had started gluing the hammers in from the bass end, and continued up into the tenor section, gluing the three spare bass hammers into the tenor shanks.

There is simply much more to piano work than meets the eye or that can be gleaned by watching a few videos. Some people do OK, but most are vastly over-estimating their abilities. Thankfully, in most cases the piano is not an irreplaceable piece.

I was wondering how long it'd take for this thread to turn into DIY-bashing, in spite of Keith asking otherwise in his opening post.

Anyone who glues bass hammers into the tenor section is pretty much a lost cause. Just please don't assume that every DIYer is such an idiot.

I wonder how many DIYers Keith has helped with parts or advice, who have actually done a respectable job. The point is, you never hear about those on the forum. It's only the failures that are presented here, for all and sundry to tear into (with varying degrees of glee).

Back to topic: I was fascinated and impressed by BDB's contribution.

A Hardman grand has so little value that it's probably cheaper to just find another equivalent core piano and take another whack at it. If he has to pay technician time to reconstruct he will be so upside down on the whole thing that it doesn't make sense to pay someone to do this. So far he's made a $500 mistake. That could easily be $5000 if he has to pay a qualified tech. I suggest either planter or salad bar as a goal with his project piano at this point.

Mark,

No one is trying to bash anyone. But, the truth is that in this case there was obviously insufficient research done in preparation for the job.

Piano tuner-technicians with years of experience might hesitate to take on a rebuilding job if they have never rebuilt a piano before. Experienced rebuilders might hesitate to take on a particular brand that may have special challenges.

My truck's engine is approaching 300,000 miles. It should probably be rebuilt. I've never rebuilt an engine. Should I just go out and have at it?

I think I gave good advice. It's time to cut one's losses. Just send it out and have it done professionally. There are probably professional rebuilders that would not want to take on this job now. There is no shame in admitting that a job was bigger than one realized.

It seems the instrument was dismantled in haste previous to recording any original data for the future.

This happens to a lot more than just the odd piano once in a while.

There are several choices to be made.

One would be to send the instrument off to a restorer and have that person complete the job.

Second would be to discard the instrument and start with another.

Third would be turning the entire matter into a positive learning/training session. This would be my choice rather than berate the person about “you should not have done this.”

Lots of people like to learn they just don’t necessarily like to be taught.

So then, have them prove they can learn.

Present the person with materials to study on how to calculate a string scale. Once completed have the scale presented to you. If the scale is a satisfactory one, have the instrument re-strung under supervision or check the work as the person goes...

Same goes for the action repairs. Following the study of the thread here and other available materials have the person present a solution.

One of the things that makes a good technician of any trade is the ability to think on one’s feet.

Hello Ed,

Most usual strike at not 88 is between 1/24 to 1/32 of the lenght. (giving those 1.8 - 2.5 mm from the capo)

The strike can be computed by following the string progression above A49 (I heard of c52 too as the beginning of the progression toward treble. ) I am unsure pure ratios are a big help, but why not.

I was explained that the strike is a straight line from 1 to 49, then could be another or the same up to 88.

Projecting 3 dots on the keybed allow to see if they line or if the treble have a different line.

But this thory will work assuming a precis ratio is known for note 49, I was given 1/8 (on a grand moderately large)

In real life it does not really exist often as such.
WHen you are on the pure ratio you are damping the corresponding partial, which is not always at the advantage of the wanted tone.

But on a rebuilding you can modify the strike if you want,assuming you can shorten or use longer shanks (if you know what you are looking for)

1/10 , 1/11 , can be find in the 5th octave of very small grands (baby grands)

I had some comments, but my Internet went out. I am at a neighbors, but will post more when I get it back (and my taxes under control!)

That depends on what you mean by "just going out and having at it". If it means simply tearing everything apart, keeping no track of parts and work steps, and putting it back together haphazardly, obviously the answer is "no".

But the answer doesn't have to be "no".

I pretty much rebuilt an engine that had broken a piston ring some 16 years ago (except for honing the block and fitting new pistons and rings - those tasks I gave to an engineering workshop because I didn't have the tools). But stripping and removal, replacement of auxiliaries, seals, gears and belts, re-assembly, etc. - all of that I did myself. The engine had done 150.000 miles. Today, 120.000 miles later, it's still running fine.

Did I "just" have at it? Yes and no. I'd worked on engines before, but never this extensively. So I got some workshop manuals, specialist tools like a decent torque wrench and engine hoist, enlisted some help for the heavy parts, and if I wasn't sure of my next move, consulted a mechanic who I know. But for the rest, yes: I basically "just had at it". And it worked out fine.

And that's what I'm getting at. There is no need for categorical, fundamentalist answers when it comes to DIY.

(My earlier post wasn't directed so much at you, by the way.)

Mark, I think things are going a little off topic, which is partly my fault, for which I apologize.

I wish the piano owner the best of luck with whatever path he chooses

-Joe

Olek,
I have found that the ultralight hammers I use in the treble allow a slightly deeper strike point. The ratios were taken from many extant pianos that I worked on and found the treble above average. I don't slavishly follow them but use them to derive the best overall treble hammer mounting points that blend into the lower compass. Also they allow for some shaping to reduce the felt over the strike point. Since most Steinways have a "crowned" string elevation at the strike point-I set bore distance for square strike in the middle and shape the treble down to reduce bore distance-this brings the strike point closer to the V-bar than was there when I glued the sample hammers. 1/17th of 52mm is 3mm-it ends up being about 2.5mm after tone-regulation. Hope this clarifies.

Yes it does . I see what you mean...high treble is having a smaller rake on the german ones .

Using very light hamners there is less impact noise I suppose.
I seem to imagine the tone.

Old Pleyels had a deep strike point in treble .

Greetings