Page #3: Preparing the Base

As shown in the photograph below, students can find the centre of their plywood base by ruling the two diagonal lines... but let them figure this out for themselves. The standard approach to locating the positions of the the two field magnets is to rule the longitudinal axis of the base and then to mark, on it, the positions 75mm from the centre, on either side of the centre. Occasionally, Mr. de Demeter's pupils have placed their field magnets on one of the diagonals. This in no way interferes with the functionality of the motor... as long as the two field magnets are located on the same diagonal.

After the locations of the three spikes have been laid out with pencil, a 3mm pilot hole should be drilled for each. Perfect pilot holes could be drilled with a drill press, which would automatically ensure that the holes were perpendicular to the base. However, that would probably not be as instructive as having the pupils themselves control the drilling angle. A hand-held electric drill could be used, but a hand-driven drill is slower and would allow more time for the angle to be corrected, if necessary. Students need to work in pairs, in order to get the holes as perpendicular as possible. The drill operator should control perpendicularity in one plane and his or her assistant should control perpendicularity in the plane which, itself, is perpendicular to that of the drill operator. All of this sounds more complicated than it actually is. A substantial pile of scrap wood or old catalogues should be placed under the base to ensure that the drill bit does not damage either furniture or floor. The photograph below gives a general idea of how the drilling is done.

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