Keen Ball Jackpot

The Keen Ball Jackpot, manufactured by Miller Cabinet Company of Kansas City, Missouri in June 1932, is an early pure mechanical (PM) pinball machine. Advertised with a walnut-finished cabinet measuring 18 by 38 by 36 inches, it featured a whiffleboard-style playfield with rubber-covered nails.

The manufacturer advertised that "every 5th nickel goes into jackpot," implying some form of payout mechanism. However, since the game is classified as pure mechanical, exactly how this payout was achieved remains unclear -- electrical operation for payout would have been unusual, though not impossible, for a game of this 1932 vintage; more information is needed to understand the exact mechanism.

Little else is documented about the machine's designer or specific gameplay layout, but the Keen Ball Jackpot stands as an example of the experimentation happening in the pinball industry's earliest, formative years.