I'm considering purchasing a used 1994 Kohler and Campbell 5'9" grand (skg-600s). Only thing is, quite a few of the notes above the G below middle C sound too bright for my taste when play with moderate force. They sound ok if played soft OR with the soft pedal. I have no problem with the notes below that G.

So I would like to know before buying how effective it would be to have a tech needle the hammers. Just wanting to eliminate that upper harmonic sharpness I hear.

The hammers look fairly worn to me but you be the judge: http://i653.photobucket.com/albums/uu259/sarta53/pianokeys_zps9ab53055.jpg

Is there much hope that those keys can be softened up to my liking?

Normally on a piano like this, hammer filing and voicing will make a noticeable improvement. Action cleaning and lubrication go hand in hand with that. As well, the regulation will need to be tweaked. Ask your technician how much a full service like that will cost.

Agreed!

And the improvement will not be subtle.

Also agreed!

The hammers are groovy but not too groovy. I would suggesting steaming it to soften up the hammers and then it will be less groovy. For me. filing is the last resort because it reduces the size and mass of the hammers.

You should talk to your technician. He/she will come up with something.

Also, i haven't heard it yet. So i cannot help much too.

My opinion is that the hammers are grooved quite a bit and will need to be filed. Steaming can make a difference but it is temporary. Once the humidity leaves the hammers, they will be back to a bright sound. Brightness in loud playing indicates they need to be voiced, deep needling on the shoulders.

Could you elaborate on what parts can use "lubrication"? I have purchased this piano and the main part I think needs "lubrication" would be the hammer shank joint, since now there are about 5 hammers that have friction and don't fall as smoothly as the rest, however in another post I was advised to have the hammers repinned rather than lubricated.

If you have slow hammers in a piano, then usually lubrication will only be a very temporary solution. The proper way to fix this is to re-pin the hammers, as has been said.
The friction of all the parts must be as even as possible before voicing (and for proper functioning of the action in general). We attain this by a combination of lubrication of many different contact points using different lubricants, and by making sure that the flange pinning is in the correct range. This is part of a full service.

Back to the original question, the trouble with voicing pianos is finding someone competent to do it. If you have someone, that person can assess the piano. If you do not, what people say is possible makes no difference.

Hmm. My experience has been different. I find that usually a shot of Protek CLP does wonders.

Sometimes, though, it is necessary to repin.

Yes, lubrication of hammer centers can help if the centers are not too tight. The OP mentions "there are about 5 hammers that have friction and don't fall as smoothly as the rest".

In all cases of my experience, by the time a player notices that the hammers are sluggish, the flanges are too tight for lubrication in itself to be a reliable long term fix. They need to be re-pinned. And usually, if the client notices five "bad" ones, there are ten more that are marginal which also need attention.

Then once you get the action apart and the weight is off the whippens there could be a lot more....

Thanks for the feedback. Ok I will remove the 5 slow hammers and take them to a tech to have them repinned.

Question: would repinning involve replacing the felt bushing as well?

Also I should mention that all 5 slow hammers are on the most commonly played keys, which are C, E, G (as the key of C is played hardest and most often).

Do hammers normally slow down through normal wear & tear this way?