"Arch" wrote: (clip) let us be the judge if your posts are boring. (clip) ^^^^^^^^^^^^^^^ Okay, Arch--you asked for it. The steady rest is a square frame, welded out of flat stock. The corners are braced with 45 degree gusset plates, so that the opening becomes an octagon. I used FOUR arms, not three, with four roller blade wheels on the ends, contacting the wood.
Here is the really innovative part: The arms are bolted to the gusset plates. They pivot--they do not slide. This works quite well, and it is much easier to build than a set of slotted arms with the required guides to keep them in line.
As the rollers are brought toward the center line of the lathe, they eventually touch each other, leaving a sort of curvilinear square opening at the center. This would limit the use of the steady rest on things like pool cues or walking sticks, where the diameter is very small. So I reverse two diagonally opposite arms on their pivots, so the wheels are rolling in two different planes, and I can go all the way down to zero diameter. (You wouldn't be able to do this on a three-arm steady rest.)
BTW, I agree with Robo Hippy, that a steady rest is probably not needed for doing rolling pins. It a rolling pin is stiff enough to flatten dough, it is certainly stiff enough to turn on the lathe.
An aside: A steady rest can by used in place of a live center at the tailstock end, if you want to turn something like a knob or finial on the end of the work. You can hold something like a drapery rod in a chuck, and turn the opposite end.
Arch, this is a test. If you're still reading this, thanks for your kind remarks.