--- On Mon, 5/18/09, Steven Smolian <[log in to unmask]> wrote: > If memory serves, the smaller 1930s > diameter was required to clear the jukebox mechanisms. The only major prewar mechanism for which the record diameter was a major consideration was AMI's which used a gripper-arm to transfer the record from the magazine to the turntable (this record changer was intoduced in 1927 and this same type of transfer arm is still used on Rowe/AMI's CD jukeboxes to this day). The transfer arm will clear a nominal 10-1/4" in its fully open position, but of course the design assumes enough clearance for the record magazine to freely move back and forth through the gap of the open arm. The other major manufacturers, Seeburg, Wurlitzer and Rock-Ola, all used horizontally moving record trays to move the record over a rising turntable in their prewar record changers, and in those the center hole was a more immediate limiting factor than the outside diameter.