Edwin Pawlowski wrote:


"Larry Spitz" wrote in message
...
Many moons ago, Mark Johnson posted pictures of his step stool which I
really liked. I liked it enough to try to copy it that is. Well a lot got
lost or changed in translation.

I built a prototype based on the dimensions that Mark used but my wife
found
it was too tall for her to sit on comfortably, so though I preferred the
proportions of Mark's I had to increase the angle of the back of the post
from 12 to 17.5 degrees as well as leave off the footrest in order to
lower
the seat height.

Here it is, both sitting in the middle of our kitchen floor and in its
normal location at the desk.

Larry


Very nice work, but I'd be afraid to step on it. How critical is the
angle?

Left-right: I'm 5'11", 190lbs. I too thought it might be unstable but when I
built the 12 degree prototype I found the physical stability to be just
fine, apart from the psychological apprehension inherent in the steps being
supported at the center only. I was concerned that my feet might slip off
the outside edges but there does not seem to be any tendency to do so
(shoes, stocking feet, barefoot).

Front-back: When I went to 17.5 degrees, I moved the post back on the base
so that the center of gravity would still be directly above the base, and
there is no problem with standing on the top step. So front to back
stability has not been a problem at either angle.

I did not calculate geometry planning on anyone standing on the top (seat),
just as most of us do not stand on the top of a step ladder. My wife, not
realizing this, and without my seeing her, did stand on the seat, also
without problems.

So as far as I am concerned the problems are visual, not physical.

Perhaps Mark Johnson would comment on his experience.