The coil winding jig, showing the top of coil form. The top surface is part of the fiberglass form. There is a brass nut in the center of the top. On the end of the shaft is a turns counter (not clear). I was trying to wind the turns with a 0.020 inch gap between them using a hand held "comb". This did not work very well. The finished coil has 525 turns and was overcoated with clear epoxy resin.