Tube plate cap size lesson learned

[mesherm]

A word to all those who would use tubes with top plate electrodes from one who has learned the hard way.
Measure the diameter of the plate electrode. Order the ceramic plate cap that is 1/16" LARGER. For example, a 6BG6G top electrode measures 3/8". DO NOT order 3/8" plate caps! They will not fit. Order 7/16" plate caps instead. Don't ask me to explain why this is because I have no clue. To me its like measuring your foot size to be 10 and asking for a size 12 shoe Yellow_Light_Colorz_PDT_09 but whatever gets the job done.