Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Effects of tilt on upright piano action?

At this post in the Piano Forum Kamin said that it is important to ensure that an upright piano sits level on the floor. In particular it is important that the piano is level from front to back, otherwise the action can be compromised.

I'm curious to know just how much side-to-side and front-to-back tilt is considered to be 'safe' for an upright action (assuming the irritated pianist hasn't already hewn into piano with an axe ).

As with so many things, the answer is "It depends." In fact, uprights can work after a fashion at angles where a grand would not.

All four casters should be on the ground in a fairly flat plane. Sometimes one corner needs to be shimmed. Twisting the bottom can cause problems with the pedals. If the top of the piano tilts too far back, the piano may double-strike more often. But it depends on the piano. I would not worry about it unless there is a problem.

If the floor tilts at a 45 degree you got problems..but I doubt that any floor is level if you put a laser on it. Unless the house has structural problems causing an extreem slant of the floor you have no problem, level or not you are not going to have any problems period

Guys !!!! the customer does not see the problem most often.

I don't mean the piano may be level from left to right, but front to back, and it MAY be seated on its casters.

during the last 2 weeks , shimming under a caster on 2 125 and 130 verticals (Petrof & Bosendorfer) changed the key dip, the hammer travel, and the attack angle of the keys.

On each there was a huge amelioration in touch and tone.

On a grand, the 3 casters are of course stable in any case (while it may be a good idea to check level from front to back)

BTW do you know at what moment during the key move, the vertical white keys are attaining level (on a grand ? a vertical ? brand x ).

The floor does not have to be level, but the the vertical piano will like to stand firmly on its 4 casters it !

Probably the front/back till is less noticeable an smaller pianos, but on a studio or more the hammer is higher on its shank.

Also, to tune a vertical, having it rocking on 3 casters ...

because of its tallness, a few mm rocking is yet changing the vertical of the piano more than one believe. Out of curiosity, evaluate how many degrees vs vertical your piano is. the keys as well have a different feel, but one have to be pianist a little to feel the difference when put back in the position it was designed for.

Issac how big were the shims and how much change occured in key dip? This premise assumes the piano keybed is torqueing because the piano is not level. Thats a lot of twist for an something glues and screwed into a long vertical side. There are no level floors and it is very common to see a buzz from a caster off a wooden floor.

Sam, for the Bosendorfer (CL 130 , 2003) a 6 mm shim had to be used, but then, the keyboard get back to its normal key dip of 10.25 in the bass, wher it was almost 11 mm, the hammer travel distance come back from 49 mm to 47 + in the same region)

Indeed the whole piano warped.
The touch changed a lot also because of the horizontal of the keys (front to back) better respected (a too slanted key is hard under the fingers) the angle in degrees was more than 5°
The caster was not touching the floor by 6 mm (the dimension of the socle is hardly more than 50 cm , 6 mm on one side is a very high value.

The Bosie was dulml and not singing, with a heavy touch, it came to life litteraly.

Same thing, less noticeable but the dip changed a little on a Petrof 125 with 5 mm shim , key dip change around 0.10 cm in the bass region , again.
There the touch became more precise , a little more tone, also.

As it is a very simple operation, I believe this is worth investigating, once you are sure the piano will not move.

For the grands I was told to check the level of the grand front to back, for tonal and touch reasons.

I use often a little bubble jauge when investigating for touch possible problems , or ameliorations. The level is not to be placed the same depending of the brands, but it is a good check, that add to other information, does provide information on the state of the key rest felt on grands, for instance.
The differences seen on the balance rail from one brand to another are related to that level position (the "gold point" in some piano philosophy !)

Indeed Bosies have a light frame and case, more prone to twist than other brands/models.

Those "detail" points have prove useful on many occasions, and are often overlooked (like the test of the tightening of the action stack screws before doing any regulation tweak on a grand).

The customer is pleased to be able to do a simple thing that can help his instrument, also. I like that kind of things !

Hi Isaac,

Piano leveling and reduction/removal of twist in the case is something that I've never read about (as a 'lay' piano owner), so your responses are very interesting. I suspect case twist is more of a potential issue in countries where it is more usual for homes to have wood floors. Here in Singapore, the floors of most homes are typically tile over concrete, parquet over concrete, or wood laminate over concrete.

Interesting. So I whipped out my carpenter's level and used it on my K-8. I know my floor is level because it was newly tiled during renovations four years ago. When applied to the top of the left and right side panels the level shows that the piano is within 0.5deg of being level front to back, with both sides showing the same amount of deviation from dead level.

The keyboard is dead level from left to right across the keyboard. But the keys are tilted ever so slightly up from back to front, so that a key is level front-to-back only when it is fully depressed. I presume that this is as it should be.

OK, I'm being an*l. Back to playing the piano.

Digitus,

considering the weight and size of the vertical piano, it is yet not so flexible.

Yes our floors are often less than level but also less than plane .
But the real modern floors are really perfect, I guess this is (again) a tolerance question.

Nowadays any warping even light is prejudicial, as not intended.

I suppose most of the time, the piano adapt and warps a little, I did not really notice that as a possible as large problems till I run across that Bosendrofer ( I simply shimmed verticals for stability reasons). Depend of the construction and the size of the piano of course.
Little pianos without back braces are may be more prone to twist severly, as the iron frame is all but a rigid part.

Thanks Isaac. I was wondering, are the keys supposed to be level front-to-back when not depressed?

No, more when they are fully depressed, slightly before, or at mid course, depending of the brand and the kind of touch.

The bottom of the key dip is an important moment, but this can be envisaged also at the moment at half course (as to be the moment where all may be perfectly aligned ,convergence)

Slighty before the full dip is common on verticals, as at full dip.

It always change something.

Piano keys are level when depressed.

I am a little shocked to hear that the pianos shimmed had such weak keybeads that would allow this torsion movement. That this would effect key-dip by a material amount is also shocking.

Hammer travel and attack angle on keys? What would be a material change in these? Enough change to affect tone?

Are these pianos really old and infirm? Loose cabinet pannels? Toe-blocks?

Craigen, I can tell you I was surprised as well, as I did not make the relation between key dip and the way the vertical seats on the floor before then.

You have a very heavy thing that stand on a relatively small rectangular socle,the pressure is very strong on each foot.
The piano iron plate is somehow flexible, the little verticals that have all case parts attached to the plate (self supported construction) may be even more sensible to warpeage.

For the key dip level at full dip, things are not as black or white as I also thought before.

On a keyboard sketch the key seem to be level at full dip, but ask the factories, and you will see the answers can differ, depending of the brand (and may be the model).

I put that on different "schools" of piano building.

Interesting to be aware of that, as I make a big use of the bubble gauger to ascertain the regulation state and cloths thicknesses used when repairing.

Level can be considered at mid course, for instance, and that is eventually a good point of view, along with other convergences, why not ?

What it does to the touch I am not yet really aware of.

On a good instrument, anything counts - what is called "concert prep" is just the added details of every normal task conducted with some attention.


Hopefully the shimming of the feet solved the problem, I hate to have to change hammer travel distance with on a new high grade instrument.
I did not mean I go great lenghts with a bubble level to be sure that the piano was perfectly straight, but at last not tilted evidently.
When shimming one have always the choice between one foot and the opposite, the vertical is generally possible then.

Because of the height of the piano a small tilt at the base can make a large difference at the top, in regard to a wall for instance.


As for future maintenance it is always easier to come from a relatively "perfect" condition of hammer spacing, travel, mating to strings, than the opposite, I've find it useful with time to get use to make no compromising on those aspects, and work on it as much as to get a feel for it, so this part of the job begin to be faster, easier, natural, less time consuming.

Eventually a less good instrument will also benefit from then (particularly the hammer travel is dealing with the effectiveness of energy transmission)

What would help me much those days is to find an electrical heating vertical shank tool, the alcohol "finishing lamp" is cute and good for the grand, but dangerous for the vertical.

Watanabe sells one, for what I know. any other source ?

I bought mine from Schaff. It is too hot unless regulated. I made an electrical box with an outlet that is controlled by a light dimmer switch. This is fastened to a board that has a rest for the tool made from coat hanger wire. I also use it for controlling the temperature of my hammer iron. About 2/3 toward full on works well.

If you are using this with 220 volts, you would have to make some modifications.

Thanks , is Schaff still selling piano parts & tools ?
I could have one made by a company that make solder irons, but I have to find a plier to adapt.

BTW I find there a neat goodie to regulate the temperature for any iron from 25 up to 500W, very precise, does not break after 1-2 years like the lamp regulator I used before (and make no noises in the electrical circuitry of the shop.

Isaac:

Schaff is still in business. They also sell shank bending pliers without a heating element. Here’s a link to their web site:

http://www.schaffpiano.com/

Thanks , again.

I keep on knocking but I couldn't come in ! a password is requested.