This Old Tube - Part 1
Cutting a hole in the bottom of a defective Eimac 3-400Z tube.
I am not the first ham that wanted to do something creative with a defective transmitting tube. So without any information to run with, I decided to see what I could to with a defective Eimac 3-400Z tube.
I already had a 10mm hole saw, that is impreagneated with diamond grit, designed for cutting holes in ceramic tiles, or glass. As shown in this photo, I placed the tube into a metal pot, and submerged the tube in water. I then placed this assembly in my drill press, although you could use a cordless drill, if you do not have access to a drill press. In this photo, I am drilling a hole through the center of the bottom of the tube.
The secret to a successful drilling operation on glass, is to use a slow cutting speed, and keep the surface of the cutting area submerged in water. Also do not rush the cutting action of the cutting tool, by applying to much pressure on the cutting tool, or you could possibly crack the tube. Proceed slowly, and you will be rewarded with a hole cut in the bottom of the tube.