I am the inventor and manufacturer of the Jump Ringer you mentioned.
I am happy you are satisfied with it. While there are cheap imitations
of my design, none compare with its precision, all steel and aluminum
construction and its versatility. You can for example, add to it by
purchasing the Oval Conversion Kit which includes five calibrated
oval mandrels and an Oval Coil Holder. For high production there is
Long Jump Ringer for machine winding and cutting 15" (380 mm) long
coils in about 3 minutes. If at any time, you feel you need technical
help, please feel free to call me at 516-333-9147.
Ray Grossman Inc.