The overall appearance is outstanding.
Threaded forms are ideal for space wound coils, which are usually very difficult to wind accurately.
Threads can be cut within 1 or 2 turns per inch for close-wound coils. Wire varnished over is embedded in the grooves threaded into the form. This prevents the wire from coming off of the coil form. This spark gap was based partially on those manufactured by H.G. Fischer Co. and other companies of the 1920s for high-power Diathermy Machines. These were made to be operated continuously, and used fins for heat-sinks and tungsten brazed machine screws for contacts.