Each spiral is 8 and 5/8" high and 2 and 3/4" diameter so the width together is 5 and 1/2". They are turned on 8 offcenters (which is 1 and 3/4") Seen from above you see a figure of 8 with a hole down the center. The steps are 7/8" diameter and 5/16" high and the amount of wood holding each together is averaging 1/8".
Comments and ?s welcome, Regards from Jeff.