Speed control

Is there any reason why I can't use a variable transformer to reduce the
speed on a mini-lathe?

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82995

This one has a listed minimum speed of 600 RPM which is way too fast for me.
I don't need much power, just want to wrap various wires around a mandrel at
a very slow rate.


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