Winchell's best-known ventriloquist dummies were Jerry Mahoney and Knucklehead Smiff. Mahoney was carved by Chicago-based figure maker Frank Marshall. Sometime later Winchell had basswood copies of Jerry's head made by a commercial duplicating service. One became the upgraded Jerry Mahoney that is seen primarily throughout Winchell's television career. The television versions of Jerry and Knucklehead also featured Winchell's innovation of actors slipping their hands into the sleeves of the dummies, giving the visual effect of gesturing with their hands while "conversing" with each other. He modified two other copies to create Knucklehead Smiff. The original Marshall Jerry Mahoney and one copy of Knucklehead Smiff are in storage at the Smithsonian Institution. The other two figures are in the collection of illusionist David Copperfield.