On Feb 19, 6:50 pm, "burly pete" wrote:
Hi
My lathe varies speed through a 2 pulley system one on the motor shaft
and one one the lathe spindle. As you change the speed one pulley will
open up reducing its diameter as the other pulley will close down
increasing its diameter. There must be a name for this type of system
but I don't know it.

My problem is the slowest speed is still too fast for the bigger
blanks.
Is there a way I can change the speed of the AC motor to compensate
for the high ratio of the pulleys.

Thanks in Advance

Peter

Sounds like my old Craftsman Variable speed 15". They are called
Reeves drives. The bottom pulley slides along a shaft and "pinches"
the belt to make it move in or out on the pulley. The upper pulley is
spring driven and you have no control over that. The bottom pulley at
some point will cease to contact the sides of the pulley and no longer
power the lathe if you force the mechanism too far. My lathe allowed
speeds between 400 and 2000 and I often found it too fast for really
rough/out of round pieces.

As far as using a sewing machine pedal, variable speed switches only
work with DC motors that use brushes. (an electrician can jump in and
correct this if I am wrong). You'll probably blow the pedal but the
smoke effects should be entertaining! Older sewing machines used heavy
duty contact points (that was before the days of miniaturization) and
on mine all I suceeded to do was fuse the heavy copper contacts
together until the fuse box kicked out.

The easy answer to your question is therefore, no....unless you want
to get into some jig building and using a second motor which you could
use only until the piece is roughed out enough for the lathe's normal
power drive to be turned on again.

Mike Courteau

http://www.toymakersite.com