Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum How can I correct wrong key spacing of an accoustic piano?

Hi there,

I'm repairing/restoring an old (1986) Zimmermann piano. I took it apart, cleaned it all out, repaired/replaced broken keys, reshaped/repaired the hammer heads, adjusted the hammer distance and key dip... so far so good. It already sounds and plays a LOT better than it did before (it does still need tuning though).

However, there's one problem remaining that I'm not sure how to fix...
How can I correct the spacing of the keys left-to-right? The gaps between the keys aren't even anymore. Some keys are too close to one another.



The problem arose after I'd re-glued all the white keys (and replaced the caps on some), and put them back in.

Can someone here tell me how to get the keys properly spaced again?

Thank you very much!

Lisa

P.S.: Sorry if there are any mistakes in my English, it isn't my first language.

What is the condition of the bushings? Is there a lot of side play ?

Are you sure you got the keys put back in the proper sequence?

'Sorry. I'm being a little obtuse. You are into an area that is a little beyond the reach of do-it-yourself repair. You align the keys by spacing the front rail and balance rail pins, but before you do that, you have to know WHY they got out of alignment in the first place. Worn key bushings are the likely culprit, but basket ball or baseball bat damage, or any other of a thousand things, can do it too.

That key top regluing worries me a little too. It's mighty easy to get them tilted, or off-center.

First you need to square and level the keys, then space at the front rail pin with the action in place. You must have good bushings to be able to do this. Also, only replacing a few (several) keytops makes for a mismatched set. Here it is obvious that the overhang styling is not the same as the originals nor is the color an exact match.

Keys must be leveled before regulating dip etc.

Based on your picture, it appears like keys were re-glued back on not level / tilting to one side. Did you clean the old glue off before re-gluing the key caps?

I can't see any real tilt. I'm guessing the old glue was removed. To me it looks like the new keytops are a significantly different thickness to the old ones so the key height is all over the place. The spacing looks like a separate issue on top of that. Seems the keytops need to be all the same for starters to get a good level.

Presuming the key bushings are tight, keys are spaced by bending the front rail pins slightly. It is an illusion, as the keys will go down to the same place, but you only compare them when they are up. (Keys are leveled by bending the balance rail pins.)

My understanding is that pre-unification Zimmermanns were pretty cheap pianos, so you should not worry too much about getting everything perfect.

Thank you for all your fast reactions!

Let me answer some of the questions first:

- The condition of the bushings is still quite good. There's almost no side play. Some bushings did swell, because of humidity. Therefore some keys did not play well at first. But by moving the keys a bit, and compressing the swollen felt, they now all play like they should.

- Yes, I did put the keys back in the proper sequence. They were all numbered.

- Two key caps ARE indeed tilted a tiny bit. These keys were quite damaged. I had to use wood filler to repair them, before I glued a cap back on. But they function fine now.
I DID remove all of the old glue before replacing the key caps.

- I didn't want to replace all the key caps, as it's supposed to stay a "low-budget" project, I got the piano for almost nothing. I did make the caps as wide as the originals, and they are properly glued. They're just a fraction of a mm higher and longer. I don't mind that 5 keys look slightly different from the others. What I DO care about is the sound and how it plays. Which brings me to the next point...

- I leveled the (first octave) keys first, and they LOOKED the same (height). However... the key dip then was different, and it didn't play very well. So I decided to go for correct and even key dip, more than looks. Like I said, how it plays and sounds is the most important to me. The keyboard plays fine now. But, the key spacing is quite uneven in some places. It bothers me. I want the keys to be all about even. The eye does want something too

- BDB is right, these Zimmerman pianos are quite cheap... but they do have a great sound. Mine has a cherry wood soundboard. The sound is very warm. The rest of the piano is cheap plywood though hehe .

So, I guess I should bend the front rail pins a bit and/or the balance pins, to get an even spacing again? Could I use normal pliers for that, when I protect the pins with a layer of foam (to not damage/scratch them)? I know there's a special tool for this, but I don't want to spend $15 on a tool that I will only use once. I want to keep it low budget and DIY.

Any tips on how to go about this?

Thanks a lot again

I have the tool for spacing keys. You could remove the key and hold a piece of wood to the top of the pin with one hand and tap the other end of the wood with a hammer. To straighten the tops, I hold a screwdriver to the top of the balance rail pin and tap.

A bit of elementary toolmaking is not beyond the average DIYer. It was always a significant part of any decent apprenticeship and true craftsmen made or adapted many of their own tools.

Some basic blacksmithing with a propane torch or the flame of a gas stove, a grindstone, hacksaw, can transform an old screwdriver, file, kitchen utensil, umbrella strut, scrap of wood, etc. into a tool that will last a lifetime and more with negligible expense. A Dremel kit has many cutting discs and different shaped grindstones you might need.

Always,always, always bend guide pins below the cloth and paper punchings. There are two main reasons for this. Any scratches will not be on the active surface and of no real consequence plus, equally important, the pin will be bent at the bottom with no possibility of bending it half way up. I have mentioned this before in these forums and was amazed at the number of working technicians who found specious arguments against this absolute basic principle. I will see if I can find this conversation in the archives. It would be funny if it weren't so serious.

A quick spritz of McLube on the guide pins will greatly increase the life of your key bushings and, of course make the key action smoother. A few minutes polishing them first doesn't hurt. This should be self evident but, amazingly, some have argued the need for this, too. This forum has come a long way.

Tapping on the top of the pins bends them where the resistance is, which is right where it emerges from the key frame. The tool will put pressure on the pin higher up, so it can nick the pin at that point, which may necessarily be above the punchings.

It would cost me a lot more time to make most tools than it takes me to make $15.

I thought it would be readily apparent that I was refering to the poster who would rather improvise a potentially dangerous tool than purchase the standard tool as used by all trained professionals.

Your comment on this standard tool and its proper and practical use isn't making any sense to me and could sound like one of the specious arguments I refered to. Perhaps I'm missing a joke. If you really are 100% serious and not making arguments for the sake of argument, or quickly rattling off an emotional response, would you care to expand on your theory?.

I have no problem with tapping the tips of the pins with a piece of wood but it is extremely time consuming to have to access the tips of the pins each time. It can be unnecesarily wearing on the balance pin holes if the keys are not lifted correctly which is highly likely in the case of a DIYer. The amateur DIYer will have this time but would do well to learn the standard far simpler techniques as used for hundreds of years by all properly trained technicians.

I would normally ignore such posts but I take the time to answer because there are people wanting to learn on this forum and I respect that above all else and I am concerned that they may be mislead by strange information. I am also concerned about the innocent tuners attempting to cure other problems beyond their skills or training and doing damage without knowing it.

Advice given to a DIYer would necessarily be different than a discussion among professionals. We can split hairs all we want, but the OP here is trying to get some basic functionality restored to a piano without paying for pro work. You don't remove the keys to tap the tops of the pins. This is sort of basic clunker clinic technique. Tap the pins. Get things straight. Don't waste the customer's time and money, and dream about your next concert prep job where you can fuss to your hearts content.

Disclaimer: I may have misunderstood what you were trying to say.

The tool used by Yamaha to spaceand align front pins is not causing any burr, of course initially their pins are in brass so they are less sensitive, but I stopped using the often seen tool with a slant to go under the punching, and I use that tool, sold by Jahnn, (and used by Yamaha) the inside is smooth and a little rounded , pushing on the pin above the punching make the pin bend lower, and does not hurt the chrome.

Straightening a keyboard, space plus level is a less than 10 minutes job once the keys are at the good level (leveling is +- 1 hour on a vertical) .


For the balcance pins I use a wood tool, the handle of the lever I use to compress a bit the balance punching (in case a note is a hair too tall)

I would not use a screwdriver on nickel plated pins indeed.

My rule is now : not bend the pins if the slant is due to worn bushings, it takes too much time to straighetn them back later.

If not on a real job, I will change the balance bushing cloth only on the side that is used, it is enough to level slanted keys. wooden clothpins "handle) make perfect bushing cauls in case I dont have some at hand...

Moistening the balance hole with 70% alcohol and letting dry help to cure pulley for the most, but a reamer have to be used once dry as the fiber raise in the wood.

Even a cheap tool will not nick the pins if you take a little time to knock the sharp edges off it. In any case, parts that rub against each other polish themselves smooth. If bushings wear out prematurely, it is most likely due to a lot of playing or bad geometry, not to roughness on the pins.

A very timely remark. Yesterday my technician brought the re-covered and re-bushed keys for my grand back and we reinstalled them. He demonstrated bending guide pins and pointed out why they should be bent only at the bottom.

The shop that did the keys bent a lot of the back checks in the process, so we did a quick back-check adjustment too. The regulation still has to wait a few weeks until our calendars will allow us to replace the hammers, shanks and damper felts, but it only took half an hour or so to get the back checks adjusted acceptably so I can play while I'm waiting. We installed one new hammer -- on A440, as it happens -- so I'm getting a hint of what this Steinway will sound like when the job's finally done.

(There was no point spending a lot of time fiddling with the back checks now because they'll all need adjustment anyway to accommodate the new hammers.)

We reshaped one recalcitrant back check using a technique the guy whose shop did the keys showed us. I separated the deerskin from the felt and slipped a shim into the gap, then flattened the front surface with an emery board. I used a folded-up piece of paper to test the method, but when we do the regulation I'll remove that and replace it with some thin felt.

The shop removed some wood from the top surface of all the whites because the replacement key covers are thicker than the original ivories (which were sadly already gone when I got the piano). My technician wasn't too concerned about any potential balance issues that might cause, and I theorized that the plastic key covers have a similar density to that of the wood they replace. Does anyone know if that's the case?

Andy

As new hammers or/and shanks mean the action have to be balanced again, the top change is not really a question, I suspect synthetics to be a little heavier depending of the style of material used

BDB. Yes, that's right. Thank you for restating my original point.

Also, while I have seen many key sets that are self lubricating and need negligible attention, there have been many where I have noticed excessive friction, even when I have taken over the care of many pianos in the same building. I have found it in many parts of the world. It could be a locality thing but it just durprises me that you have never observed it. could be you have a predecessor that took care of this, it certainly doesn't need attention very often.

Finding the exact configurations for me in a commercially made tool is difficult. My own tool for this job is perhaps 40 years old and I did knock the edges off it when it was new.

Andy, yes, you are right, it is always a good idea to look to the key balancing when any parts are replaced and when keys are spaced and squared,there may be back check realignment.

I have a peice of 1/4" brass rod I glued into a plastic handle and then filled a curved arc into the tip. Angled at 45 degrees and held on the tip of the pin I give it a whack with the palm of my hand and it tips the pin right at the base, below the punchings. Any forked tool I've seen for doing this at the base actually puts force on one upper side right at the top of the punchings or above. This is the worst place to put a nick or chip off some plating from the pin. Every time the key bottoms out, it wears the bushing right where it bends into the bottom of the key.