Greetings. I am the owner of M&H BB build around 2008. I have noticed that it is hard some times to play passages in sharp keys or you have to "Climb" over the black keys. I find it exhausting and I am always conscious about it. Is there a specific key depth on a grand piano?? Can it be changed without affecting the regulation of the keyboard?? Can the black keys be lowered a little bit without affecting it's playability? I also find that the separation between black keys is not as wide as in other pianos. Comments??
Thanks on advance

Without seeing the piano, can't say but your tech will be able to tell.

When a black key is full down, how high is it above the white keys? If it looks like you could have them finish up lower without them burying themselves below the level of the white keys then you can have the black keys lowered.

This may help with the spacing because the fatter part of the black key is lower. If not, it is possible to change the spacing of the black keys quite easily.

Greetings,
If the sharps are more than 13 mm, (1/2 inch) above the naturals, it is going to feel high. If either key depresses more than .410" (about 10 mm), it is going to feel deep. The sharps must not go below the surface of the naturals, and it feels better if there is at least .040" of the sharp extending above the naturals when depressed.
These are the basic dimensions of key travel and relationship to each other. Your piano probably has some variation, but the 1/2" height on the sharps is pretty widespread. If possible, I like to set them a little lower,but the action ratio determines how much dimension/aftertouch etc. you will actually have.
Regards,

I have used a sharp height of 12mm. since my first rebuild 20 years ago. I hated that 1/2" height. If you check the sharp height on competitive instruments, you will find a concensus at 12mm. The 10mm dip is likewise better than the 3/8" dimension specified by some and is likewise a constant.

HI . Thanks for your reply. I checked the height of the black keys and it seems to be at 1/2 inch. According to my calculations 1/2 inch equals 12.7 mm which 0.7 mm would seem negligible. When the black keys are depressed, the rear of the key seems to be higher that the front. I assume that this is normal due to the angle. Is it difficult to lower the sharps without ungluing them from the actual key them and filing them?? Will the keyboard look a little goofy?/ Thanks to all for your responses.

Yes, and Yes.
Regards,

Key height is set by shims, not by adjusting the actual thickness of the keys!

One approach is to set the black keydip to provide equal aftertouch to the whites. Actual dip distance may vary from white dip.

Thanks again to you all for your kind replies. Great information and it makes sense.

Please, please tell us that you are not even contemplating doing anything remotely like this to a piano (even if it is your own)!!!

Sorry, .7 mil is not negligible.

This could be a problem with regulation - the way a piano "feels" could be giving you a false impression that the dimension is incorrect. How long since it's been regulated. Even voicing can give a false impression.

If it's not had a regulation recently, I'd suggest getting that done - and the technician would be able to answer your questions about key depth.

PLease , worry not. I have a very skilled technician and this will be addressed by him. I will proceed with caution since it sounds like it can change things dramatically. BTW. The piano has been regulated,voiced and tuned to a concert level. Thanks again to all

You mean .7 mm, I think. The term mil is most typically used to mean .001".

.7 mm is less than the difference in the height of a black key over the white keys at the front compared to the height at the back.

I am not sure I get it. A fairly new, high end piano, recently regulated to concert specs.... But you find it hard to play and ask how to change things.... No offense intended, but if the piano is in perfect shape, that only leaves the player, doesn't it? Did you recently upgrade from a digital that had an "easier" touch?