Are you trying to use an octal tube to replace a 4-pin? I've gone the other way...making an adapter for a tube tester so I could test 4-pin tubes in an octal socket. You could try making an adapter by carefully breaking an old 4-pin dud tube and cleaning out the base. Find some plastic (PVC or ABS) pipe that you can glue to the 4-pin base. Usually a 3/4" or 1" long spacer works well. Connect wires from the 4 pins to appropriate pins on an octal socket and glue the socket to the plastic pipe.
Rich
:Has anyone developed a way to seat and hold an octal socket into a 4 pin socket?