High Frequency Apparatus Page 63

INDUCTION COIL OUTFITS 63 The secondary sections may be wound either in a lathe or else upon a form mounted in a simple winding rig such as the illustration suggests. The outside diameter of the micanite insulating tube over the primary will be approximately 24 in. and this shall therefore be the internal diameter of the sections. The form consists of a disc of wood nailed to one end of a short cylinder of wood and the whole mounted either in the lathe or in bearing supports as shown. The cylinder should be 24 in. in diameter and about 2 in. long. In starting the winding of a section, the wooden cylinder should be covered with a layer of cord to make possible the removal of the section. The first layer of olded paper may be wound upon the cord which is pulled out after the section is finished. In the first paper layer there should be six or eight thicknesses of the oiled paper to make a mechanically strong support for the winding. The starting end of the No. 32 S. C. C. wire is soldered to a piece of thin copper ribbon inserted between layers of paper, and the first layer of wire wound until 112 turns have been placed. At this juncture the winding should be an inch Turn in this direction Wooden disc attached to cylinder This position for sections #1 and 3 Reverse for #2 and 4 HO Pasten securely to bench Section finished Fig. 7.-Winding apparatus for secondary sections