On Mon, 17 Oct 2011 17:15:31 -0400, Jim wrote:

This posting may be a little difficult to present clearly. I
"had" a no-name office chair, at least I did until last Friday
evening. This be a gas strut supported swivel chair that is
height adjustable. Perhaps 10 years old.

While turning slightly I suddenly found myself on the floor. The
top bracket, a box shaped assembly to mate the chair to the gas
strut portion had sheared.

Hate to toss out the chair base/back unit as it is nearly perfect.
Searching online (eBay) for replacement base assemblies show
they run more than just buying a replacement chair.

If anyone here has had similar experiences I'd like to learn some
options.

I've converted a few rolling/tilting/adjustable height office chairs
when either the top or bottom went bad. No gas cylinders though.
Pick up office chairs at thrift shops. Goodwill, Salvation Arrmy,
etc.
Just of matter of salvaging top or bottom and screwing one piece to
the other. Just make sure what you buy can be butchered to fit what
you want to keep.
You might need some patience to wait for the right chair to show up.
My wife shops these stores often and always runs across what I need.
She'll call me and I'll go down there and load it in the car.
Sometimes in 2 pieces.

--Vic