Very happy with my regulation tweaks, but...

[alexwaston]

Being mechanically minded, and a tweaker, I've been exploring regulation of my own grand piano.

So far, I've been very happy with the results I have achieved. I've regulated the let off and drop, and most recently, have been playing with the Repetition Lever regulating screw, predominantly on the treble end.

What I've managed to achieve is a much faster repeat on the treble end (by allowing the jack to slide back under the knuckle much more quickly with a very small release of the key).

Generally, I am now very happy with the way the piano plays, however, I've also just now noticed that when the hammers come back to rest, they don't all come back to rest at the same height, and depending on how slowly and softly I release the keys, the hammer may come back to rest higher and if I play the key harder and release quicker, the hammer tends to come back to rest at a lower position. I've noticed this behavior only on the keys where I've adjusted the Repetition Lever regulating screw.

While this doesn't appear to affect the control or the playability of the piano, the OCD part of me is finding it visually annoying to see the hammers at rest in all different heights.

Wondering if anyone here knows what I am talking about, and would appreciate if anyone can give guidance on what I can play with to reduce this effect.

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[Colin Nicholson]

This is a common problem for the DIY enthusiast, and if you upset the regulation process mid way, you are best contacting a professional to do the job.

The repetition springs have been regulated at slightly different tensions, some with more tension - which will allow the hammer to rise above the rest (rollers resting on the rep lever), and the lesser tensioned springs will allow the hammers to drop - so you get a Mexican wave? The tension of the repetition springs must be set exactly the same so the hammers "hop".

It seems you have skipped some of the initial vital repetition processes, and jumped to let-off?

You have not mentioned the grand piano name/ model/ size?? .... most grands are different in their regulation process and specs depending on length etc.
The let-off and drop is just the tip of the ice berg, usually adjusted at the mid point of regulation.
Hammer blow and key dip are the first vital adjustments - must know the ratio and measurements first before anything else.

For a small fee, email me your piano name/ model/ action type, and I can provide you with the correct spec and process.

Colin

[Colin Nicholson]

Some more info....

Depending on if you want perfection or not and for all hammers to be perfectly level, and all at the same height (bass hammers will be higher on an over-strung piano) - you need to purchase a grand piano regulating rack; a device that is assembled and adjusted to simulate the strings, so the hammers hit a wooden rail instead of strings - so much of the regulation must be done with the action out. The hammer height (to string) MUST be set correctly first with a sample hammer, then tested.... then the rest adjusted to the sample. The hammer blow distance varies from piano to piano. If there is no spec for your piano, use the height you have, so long as the hammers do not bubble.

To adjust the hammers so they are all level, work outwards from the middle, so all adjusted from your sample, by turning the brass capstans under the undercarriages (the capstans are screwed into the wood of the keys) - using something like a crooked knitting needle. Some grands (German) have rocker capstans and have 2 screws to adjust per note. The grub screw farthest away is to adjust the height, and the nearest screw locks the capstan into place.
You must have the action out to do this, so you can work at eye level, with your chin almost resting on the keys.

Before all of this is done, the repetition springs must be tensioned enough so the hammer rollers rest on the rep lever (not the jack) .... so any weak springs will show up re hammer height being lower - so get them tensioned more, then adjust the rep spring tension properly at the end of the process. You also need to use a regulating rack to strike the hammers hard against the rail, then when the hammer 'pops' during release - this slight bobbing of the hammer means the springs are at the right tension - if no bobbing, springs too weak, if a fierce bobbing, springs to strong. Some springs may need replacing if the adjusting screw has reached its limit.

Hope that helps......