This drawing shows the dimensions that I typically use for a pinball machine. They are not the ones used for "Alice" but they are very similar. They are the dimensions that I used for a later machine, “Galapagos” . The width of the play-field is the same a standard sheet of plywood (in the UK). The thickness is 12mm. The diagram shows the main holes and slots that I drilled and routed through the thickness of the play-field board. This view is from the top of the play-field, when mechanisms and electronics are fitted to the rear many more holes are needed and will be positioned when the components are placed in position. Care is needed to ensure that these rear holes do not penetrate the front surface.

The top sets of holes and slots are for the guide posts and roll-over switches.

The lower set (circled) are for the pop-bumpers. Dimensions for a set of holes for a pop-bumper are given later.

The lower triangles represent the rubber “rings” that form the bumpers, and the hole positions for their support posts.

The slots within the triangles are for slingshot mechanisms

Most important perhaps are the position of the holes for the flipper bats. If the holes are too far apart then it is too easy to loose the ball as it falls between them into the “drain”. Too close and the call cannot or seldom falls between them. On the next machine I reduced this 150mm dimension slightly so that it was not too easy to loose the ball.