[pianotech] Piano on Soft Carpet

[Ron Nossaman]

Floyd Gadd wrote:
> I've read of a method of levelling grandfather clocks on soft carpet that
> uses flat head screws driven through the carpet into the floor such that the
> heads of the screws are level with the top surface of the carpet.  The clock
> sits on on the heads of the screw rather than on the carpet, and thus is
> stable.  The screws can be adjusted to achieve a perfectly level clock. If
> this piano has no casters, perhaps its points of contact with the floor are
> large enough that a method like this might work.  Trying to balance casters
> on the heads of screw would of course be an exercise in futility.

An interesting thought. The problem is, of course, that the 
PSI load on the carpet from the bottom of the piano isn't high 
enough to compact the carpet enough to not "float" the piano 
on the nap - at least not right away. Sitting the piano on 
four plastic caster cups with the ribbed undersides, so 
they'll crush the nap and padding and more nearly make solid 
contact with the floor, or on a half dozen marbles to similar 
effect should minimize rocking. Yes, it will screw up the 
carpet. So what's the priority, carpet preservation or piano 
foundation solidity? Also, even if the piano's rocking on the 
carpet, it's severely back heavy, and isn't likely to fall 
forward. A spacer attached to the wall at just below lid 
height, that the piano can be slid (slud?) back against will 
have a similar effect with the piano floating on the carpet.

Or they can lay a concrete A/C condenser pad down and put the 
piano on that.
Ron N