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

[Dale Parfitt]

Hi Alex,
Very neat. Can you tell us what tubesters you have made- that is, what tubes have you  replaced?

Dale W4OP


-----Original Message-----
From: Boatanchors [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Radio AI2Q
Sent: Friday, August 19, 2016 12:58 PM
To: Bob Groh
Cc: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Has anyone ever cut the glass top off a miniaturetube to re-use the base?

Bob, I was able to solder to the wires inside the tube base. These little "tubesters" worked just fine!  Cutting into the tubes with a Dremel tool turned out to be very easy, too.

Have fun.

Vy 73, AI2Q, Alex

  ----- Original Message -----
  From: Bob Groh
  To: Radio AI2Q
  Cc: McDonald, J Douglas ; boatanchors at mailman.qth.net
  Sent: Friday, August 19, 2016 12:54 PM
  Subject: Re: [Boatanchors] Has anyone ever cut the glass top off a miniaturetube to re-use the base?


  Alex, how do you connect to the pins inside the tube base?  Any special tricks needed?


  Bob Groh, WA2CKY



  On Fri, Aug 19, 2016 at 11:43 AM, Radio AI2Q <ai2q at roadrunner.com> wrote:

    When making FET replacements for 7-pin and 9-pin miniature tubes, I use a Dremel tool with a cutoff wheel and run it at the highest speed. The wheel actually melts the glass as it "cuts."  You can see the red glow of the molten glass when doing this. After the tube is cut open I insert my own label (!) and then glue the tube back together before placing it in the circuit. I have done this with 28V circuits in an R-392 receiver.

    Vy 73, AI2Q, Alex
    Member: ARRL, FOC, RSGB, CWops, QRP-L, Antique Wireless Association, New England Radio Discussion Society, DXCC Honor Roll, 16ØM DXCC, 8ØM DXCC
    http://ai2q.org



    ----- Original Message ----- From: "Bob Groh" <bob.groh at gmail.com>
    To: "McDonald, J Douglas" <jdmcdona at illinois.edu>
    Cc: <boatanchors at mailman.qth.net>
    Sent: Friday, August 19, 2016 11:23 AM
    Subject: Re: [Boatanchors] Has anyone ever cut the glass top off a miniaturetube to re-use the base?



      Thanks, Doug.  I have found the pins (both tin and gold plated from
      Keystone) at Mouser.  In lots of 100, tin are about 11 cents each - not
      bad. Gold about 2 to 3x (I didn't capture price).  Not sure about length -
      need to check that.

      At this point, most acceptable option (i.e. inexpensive with reasonable
      quality) seems to be short pieces of 18 AWG copper wire inserted in 7 pin
      sockets.  The Keystone pins are a nice option - again inserted backwards
      into 7 pin socket and soldered (again I need to check length).

      Your idea of drilling holes et al in pill bottle, pc bd, whatever - problem
      with precision although with a bit of work one could come up with a drill
      template. Also still leaves idea of having little custom pc board done -
      still got to look at that (maybe $2 for pc board plus $1 for pins - not
      bad).

      So still more to go.  Great batch of ideas from everyone.

      73
      Bob, WA2CKY

      On Fri, Aug 19, 2016 at 10:07 AM, McDonald, J Douglas <jdmcdona at illinois.edu

        wrote:



        You can buy gold plated pins that plug into those sockets.

        Solder wires to them, drill holes in a small cut-off plastic bottle,
        insert pins, and fill with epoxy or
        sensor-safe silicone.

        Just a thought.  I still have a very few plugs left over from the 70s,
        which I am slowly using up.

        Doug McDonald

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