Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Question about dumpers (good for adjustement or swap?)

I know what you mean, Isaac. I think the manufacturers that recommend finger tight use a screw with a sharper point. It feels that way but, to be honest I never looked.

Does anyone out there know?

You think of the heagonal screw head ?

No, Isaac, the usual looking ones.

There's nothing wrong with politely correcting someone. I appreciate it when it happens to me.

Agreed, it was done in a very gentle way. No big deal. In this case I think it was warranted because the word "dumpers" might carry with it lots of other connotations and I'm sure Karel will be happy to avoid them. I speak a couple of other languages and I'm always happy to be corrected because it helps me to improve my clarity and expression.

Guys, I'm really sorry for this mistake and thanks a lot for dampers correction! :-) I've already discussed the issue with my technician and the piano owner and he promised to have a look at it so I'll see what happen. Good that dampers may still be used and not exchanged although a price for a set of new from Detoa is not that high here. The other question is how they will fit. Err, another possibility is just to exchange felt on dampers as also sales person from Detoa noted. So well, I'll leave this issue to my technician and will rather deal with my playing ability and practising. ;-)
Thanks a lot for all provided information, I really appreciate it!
Karel

All the regulation manuals I know state to tighten all screws finger tight temporarily, during regulation, then to tighten with a screwdriver to prevent loosening from the impact and vibration during playing.

Which manufacturer recommended finger tight?

I do not understand why they do that.

If the flat portion of the felt rests on the strings then the wedges of the other side won't fit on the strings and visceversa, if the wedges engage the strings then the flat felt won't rest on the strings.

Can someone explain the reason for using flat/wedge felt on a single damper?

Also, what kind of precautions must be taken when replacing the felt in such dual shaped dampers in order to have both kinds of felt working appropriately?

I agree with Jurgen - finger tight is risky. If the dampers get bumped they may easily go out of alignment. Also, I do a lot of voicing with a chopstick tool, and the sometimes I work between the dampers - if they are not screwed down fairly firmly they will move.

At Yamaha I was taught to tighten them in two passes - the first just tight enough so that they can still be rotated with duckbill pliers if necessary, and then a final pass where they are tightened enough so that they can't be easily moved.

The beanbag device that rests on top of the damper heads when tightening screws helps a lot to keep the dampers held in place while tightening the screws.

I find the idea good so I tried, but it can move your damper heads. What make the damper twist is the pressure of the screw, more if the screw is overly tightened so I understand what mean Rxd with "finger tightened") holding the wire with round pliers just above the lever is how to secure it.

The round pliers are also good to tap on the lever lightly to make it go a little lower (I have a leaded wood dowel to tap on the damper head to do the opposite)

Damper pliers are also useful in case the wire have to be twisted a little (with round nose pliers)

Learning to hold quietly the wire with the pliers is not as easy, but then the damper does not turn.

A small pry bar allow to have the same motion than with the pedal, but in the cavity.

@Gatzar : dampers are mixed flat plus double wedge to have a more progressive damping, in my opinion the height of the felt is of course important, but you may have noticed that dampers often rise one side sooner than the other (they are well guided then).

There are different type of damping "effect"/progressiveness depending of the orientation of the fiber, and how much the head is level to the wire surface.

Not so easy to have good damper felt those days it is worth keeping the old ones if you dont have good replacement. (The Detoa felts are medium quality, they are too soft and deform easily) A damper is always" damping" a little like a piano is always "playing" good damping mean you can extinct the tone progressively without ringing notes or parasites

The double wedges on the Foerster of the pics are properly cut , no wedge protuberant under the wire (or very little).

For damper work on Steinway style systems I find important to have the good quality/thickness of felt (I have seen plenty mounted with too soft felt that added a lot of friction and wear too fast)
For Steinways I buy strips of the good felt directly at S&S, not very expensive, Jahnn had a similar quality availeable.

The amount of raise of the dampers is important - 5-6 mm for the flat dampers depending of the piano and the unacorda mechanism, if any.

The sharps have the dampers raise more than white keys,(generally) the more the dampers rise the more there will be difference between white and black keys.

A jig laid on the stretcher is very useful to verify the squareness of the head, the angle of the wire vs the head, etc.

Thank you for the explanation Isaac, that makes sense.