The armature is supported in position over the electromagnets by means of a standard bent out of a strip of sheet brass. The details of the standard are shown in Figure 36. The standard is fastened to the base by means of two small wood screws.
FIG. 35.—Details of the Armature Shaft.
The armature should just clear the top of the electromagnets when the lower end of the shaft is resting in the socket in the yoke. The shaft should be perfectly vertical and revolve freely without friction.
The lower end of the shaft carries a small brass contact which is forced into position. The exact shape and dimensions of this contact are shown in Figure 37. The holes through the center should be slightly smaller than the diameter of the shaft, so that when the contact is forced into position it will remain secure and not move.
The Brush which bears against the contact is illustrated in Figure 38. This is cut out of spring copper or brass and made according to the shape and dimensions shown in the illustration. The brush is fastened to the base by means of a round-headed brass wood screw.
The proper method of assembling the motor and its appearance when finished are best understood from the illustration in Figure 39.
FIG. 36.—Details of the Standard which forms the upper bearings.
The Binding Posts consist of machine screws provided with hexagonal nuts and thumb screws, such as that supplied on dry batteries. One binding post passes through the end of the brush and connects with it. The other binding post is mounted at the left hand forward corner of the base. One terminal of the electromagnets leads to this binding post. The other terminal is placed under the head of one of the screws which hold the standard to the base.