[ Jean-Marc Cerutti wrote in 120825 MMDigest:

> It is always very difficult to give the right speed at the endless
> screw and I suppose there's an easy way ...

The speed is regulated by the amount of air resistance.  If you close
the fan blades in, you'll get _more_ speed, if you open them up, you'll
get _less_ speed.

Nancy Fratti - Nancy Fratti Music Boxes
Canastota, New York, USA
http://www.nancyfrattimusicboxes.com/