[Boatanchors] Has anyone ever cut the glass top off a miniature tube to, re-use the base?

[Marvin Match]

I have made these plugs before. It's tedious, but you can do it.

1. Lay a piece of heavy paper on a block of Styrofoam, take a 7 or 9 pin 
tube and push the pins through the paper. Some tubes have sharp pins, 
some don't. Obviously sharp pins are better, but either will work. Draw 
a circle around the tube.
2. Remove the tube and paper from the Styrofoam, pull the tube pins out 
of the paper and cut out the circle with a pair of scissors. Don't cut 
up to the circle line, leave an extra 1/8 inch or so.
3. Now gather up some wires to make pins. Cut-offs from resistors or 
capacitors work OK. Some or maybe most of them are actually tinned steel 
wires, not copper. Make the pins longer than needed because you can 
always trim them afterwards.
4. Riffle through your junkbox and find a 7 or 9 pin wafer socket. You 
want one of the brown ones made out of two pieces sandwiched together 
that has little holes for the pins, not slots. Put a layer of Scotch 
tape over the top of the wafer socket, then assemble the plug by pushing 
your pins through the holes in the paper disk, through the scotch tape 
and into the wafer socket.
5. Cover the backside of the paper disk with epoxy which glues the pins 
to the paper in perfect alignment. The Scotch tape on the wafer socket 
is to prevent the epoxy that will invariably leak past the paper disk 
from sticking to the socket. Build up the epoxy in 2 or 3 layers, 
allowing it to almost set between layers.
6. After the last layer of epoxy has set, if you were lucky you can pull 
your new plug out of the wafer socket. Be careful because it's still 
very delicate.
7. Trim up the epoxy and paper around the edges back to the circle you 
drew around the tube in step 1 with nail clippers so the paper/epoxy 
disk is round-ish with no jagged edges.
8. Carefully wrap a layer of Scotch tape around the disk, forming a mold 
that stands proud of the disk about 3/8 inch.
9. Fill the cavity with epoxy. Do this in stages, because sometimes a 
large body of epoxy will crack due to heat generated during the curing 
process. After it's set, remove the tape.

Back when I could see better, this was pretty easy after about the third 
plug I made. Once you get the hang of it they actually look pretty good. 
Solder to the pins quickly with a hot iron, because the epoxy burns 
easily. A sleeve of heat-shrink about an inch or a little more over the 
whole assembly and you're done. Obviously not as rugged as the real 
deal, but perfectly workable.

I've made other plugs this way also, like a plug to connect a VFO via a 
crystal socket using pins from an octal tube, when I didn't have a 
crystal that I was willing to sacrifice for a plug. You can make this 
plug with the cord exiting the side rather than straight out the end if 
you want to. That way it lays along the face of the transmitter rather 
than sticking out into your operating space.

7 3
KA7TPH