John Haskey asks for advice on cart-building.  I might as well share my
experiences in the field.  I built two carriages for player pianos when
I thought I was going to make a business of offering mobile player
piano services.

Presuming you are only going to wheel the cart by hand (no motor) so
I would not recommend any suspension.  The suspension adds a lot of
weight.  If you use wheelbarrow size wheels with pneumatic tires the
tires are suspension enough; you won't likely be rolling it on any
gravel or rough surfaces.  I never went on anything but pavement and
grass lawns.  I built rectangular frames of square tubing that fit
precisely under the bottom of the instrument.

I consider it important that such a cart have only three wheels if
there be no suspension.  That eliminates the possibility of one wheel
leaving the ground, which is not a good feeling.  I put one castered
wheel forward with a wagon style handle attached directly to the fork
of the caster so it turns directly with the handle instead of being
forced to turn the way casters usually work.  Naturally the other two
wheels are in the rear.  I arranged that so that the axles (each wheel
on its own) slipped inside frame members in a way that the tracking
width can be adjusted: narrow (no wider than the instrument) for
doorways and wider for rolling on uneven surfaces.

Some kind of stabilizer(s) to keep the instrument from resting
solely on the wheels (tiny contact points) during play is desirable.
I started with putting blocks under the frame upon arrival but
eventually cut up a C-clamp and added the screw part to the frame so
it could be screwed down to contact the ground.

I built a tilt-trailer to haul them and had tracks in the trailer for
the wheels, a winch to pull the instrument on board, and holes through
the frames of the trailer and the carriage so I could pin them together
with a 3-foot by 3/4-inch steel rod pin.

I have since realized that the vocal part of my show is the part most
audiences are interested in.  I made DVDs of my piano rolls on the
piano and that's my accompaniment.

Best of Luck to you!  Sharing these toys with others is the most
rewarding part of having them!

Lee Rothrock