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.

"william_b_noble" wrote in message
s.com...
well, here is what you do.
1. put the belt on one set of sheaves. rotate the motor by hand and count
how many turns of the motor equals one turn of the spindle. Write that
down. Repeat for each of the other three belt positions.

2. locate the nameplate on the motor and read out the RPM - if it's not
listed,or you can't find the nameplate, assume that it's 1750.

3. multiply each number you wrote down in step one by the motor speed you
located in step 2. Write those down.

4. print up a nice fancy lathe speed table using the numbers in step 3 and
put it next to your lathe.


"Lauritzen" wrote in message
news:4bzrc.8354$g71.4130@clgrps13...
I have a 1970s Rockwell lathe that has a AC-motor belt-drive. There are
four speeds. Any idea on how to determine the RPM?

Mike