National RF now manufactures new plug-n coil forms.
These forms are machined of high-impact plastic and mounted to a standard 8 pin "octal" plug. The form measures just slightly over 2 inches in height with a coil diameter of 1.5 inches. An area of 1.3 inches is machined for the actual coil, or coils, to be wound. In addition, a groove is machined in at the top that provides a convenient finger grip for inserting or removing the coil from a socket. And with a total of 8 pins available, the customer can bring out numerous taps, or wind separate "coupling" coils on the form.
Matching octal sockets are available as well.
Note to vintage radio buffs: these plug-in coils are not intended as restoration forms for older equipment. They are made new, and intended for the experimenter or radio enthusiast who needs to insert different coils for different frequency operation of home-made receivers or transmitters.
Type NPG-1 Plug-In Coil Form $9.75 plus $4.50 for shipping
Analog Display Dials
HROII-PD and HROII-PDA