[pianotech] Fixing flexy stage dolly

[Mark Schecter]

Hi, all.

I take care of a Steinway D at a local school which rides on a stage 
dolly. Yesterday I tuned for a pianist who found the movement of the 
piano under heavy playing to be disturbing. When he would play big 
octaves in both hands, the piano shook in a way he could feel through 
the keyboard. As Jurgen mentioned recently, the arms of the dolly are 
like big leaf springs. I have an idea to improve this for which I'd like 
to get your feedback.

Because the piano legs rest on the ends of the dolly arms, outboard of 
the wheel location, the wheels act as fulcrums, and the weight of the 
piano lifts the central arm-connecting part of the dolly. If you press 
down on the rim of the piano, the center of the dolly rises toward the 
main rim braces. I am thinking if I put a vertical post between the 
dolly and a main rim brace, it will greatly reduce the dolly's freedom 
to move, thus less flexible. I would make it long enough to be in 
compression, rising from the central arm connecting plates of the dolly, 
upward toward the underside of the brace, and wedged between the two.

Has anybody tried this? What were the results or problems? Do you have 
any suggestions for improvements to this idea? Thanks very much!

~Mark Schecter