Make the core by bending two 4" nails in the middle at right angles. Space the heads about 3" apart to form a horseshoe. Wrap together with two layers of tape.
Wind about 400 turns of wire around the center. Leave 4" of spare wire at start and finish. Attach to wood base with staples at each end of the wire. Small brads, bent over, will do just as well.
Step No. 4—Armature Supports and Brushes
Scrape the insulation from the ends of two 6" pieces of wire. Tack them to the base and bend them as shown to make brushes.
Drive two pairs of 3" brads into the base about 3-1/4" apart and in a line midway between the field poles. Wrap wire around the supports to form armature bearings.
Scrape insulation off ends of wire from the field. Connect one end to a brush wire.
Assemble As Shown