Uh, not really. Read it again. Guess I threw you with my "reality" point.

I use it with kids in class because they learn math with calculators, and if
they plug the wrong value in, they get trash - unless they have an estimate
of valid range or "reality" point.

Motor speed times ratio of motor to spindle pulley (diameter,
circumference, no matter) equals spindle speed.

Thus if 1.5 on motor and 4.5 on spindle - 1/3 times 1725 = 575 - pretty
common.

"Bob Pritchard" wrote in message
...
To find a minimum speed the smallest pulley would be on the motor.
With a 4" pulley on the headstock and a 2" pulley on the motor the ratio
is 2:1
A normal motor of 1725 divided by 2 would be approx 862.5.
Your theorie suggests a high speed setting with the large pulley on the
motor.

Or: Measure your pulley sizes - outside OK, since you're interested in a
ratio. If the Pulley on the motor is 4", lathe 2", the ratio is 2:1.
Multiply by the motor speed.

If I were a betting man, I'd say minimum is 600.


Bob, Naugatuck Ct.
http://www.outofcontrol-woodturning.com