[R-390] Tube cutting 101

Thu, 17 Jan 2002 12:13:53 -0500

I have had mixed luck with a small file. I etch a line around the tube and 
then tap the tube with a screwdriver handle. Most of the time it will break 
clean.  John

>From: "AI2Q Alex" <[email protected]>
>Reply-To: <[email protected]>
>To: <[email protected]>
>CC: "R-390 (E-mail)" <[email protected]>
>Subject: RE: [R-390] Tube cutting 101
>Date: Thu, 17 Jan 2002 10:54:20 -0500
>
>Yup, I tried this too Ray, but didn't have a good enough assortment of
>Nichrome wire.
>
>73, AI2Q, Alex
>
>-----Original Message-----
>From: Ray, W2EC [mailto:[email protected]]
>Sent: Thursday, January 17, 2002 8:43 AM
>To: [email protected]
>Cc: 'Barry Hauser'; 'Steve Goode'; [email protected]; 'Roger L
>Ruszkowski'
>Subject: Re: [R-390] Tube cutting 101
>
>
>I seem to recall a method where you use a small wire that you hook up to
>a 12 volt car battery until its glowing good and hot, then quickly wrap
>it around the tube where you want the break to occur and dip it quickly
>into water. The hot wire heats the tube at the break point and the rapid
>cooling snaps it cleanly off. Anybody remember/try this technique?
>
>73, Ray  W2EC
>
>
>AI2Q Alex wrote:
> >
> > Hi Barry:
> >
> > After trying to cut open some sacrificial tubes using a few
>scribe-and-snap
> > techniques, I arrived at a better way using a Dremel tool and thin 
>cutting
> > wheel.
> >
> > I place the Dremel motor in a drillpress vise, and set the vise on my
> > workbench so that the direction of rotation is away from me. Donning
> > protective glasses, I then crank the motor up to top speed. Holding the 
>7-
> > or 9-pin tube using gloves, I carefully rotate it against the cutting
>blade.
> >
> > The point of contact actually glows red, which leads me to believe that
>the
> > friction at that point may actually be melting the glass as well as
> > "cutting" through it. In any case, the result is the same: I get a nice
> > clean break. You have to fiddle a bit to get the right pressure and 
>speed
>at
> > which you rotate the tube against the wheel, but after a short learning
> > curve, you can open these jobbies up and enjoy a low scrap rate.
>Naturally,
> > you don't do this with rare tubes such as 7360s. You do it with defunct
> > 6BA6s and 6AQ5s and the like.
> >
> > Once opened, I remove the innards, and solder-in my solid-state devices.
> > Closing the tube (after inserting a mandatory slip of paper with my
> > callsign, date, tech info, etc.) is done with some Crazy Glue.
> >
> > Vy 73, AI2Q, Alex in Kennebunk, Maine    .-.-.
> >
> > -----Original Message-----
> > From: Barry Hauser [mailto:[email protected]]
> > Sent: Wednesday, January 16, 2002 1:02 PM
> > To: [email protected]; 'Steve Goode'; [email protected]; 'Roger L
> > Ruszkowski'
> > Subject: Re: [R-390] 6DC6 Replacement
> >
> > Alex wrote:
> > .> I confess! I've poked JFETs into both 26C6 mixers on my R-392, and
>those
> > > 24-V stages work really well. I used a Dremel tool cutter to scribe 
>the
> > > glass of 7-pin miniature tubes, cracking them open and removing the
> > innards.
> > > I then soldered the JFETs with drain source and gate connected to the
>old
> > > plate, cathode, and grid leads, respectively. After inserting a label
>with
> > > my callsign on it, I then glued the glass envelopes closed. I popped 
>'em
> > > into the R-392, where these solid-state jobbies perform flawlessly. I
>can
> > > elaborate about the glass cutting procedure if you're interested.
> > .
> > Am I to understand that you failed to replace the vacuum with fresh, uh,
> > nothing? ;-)
> >
> > For effect, you're allowed to add a mini orange LED for glow, but it
>should
> > be driven by a EEPROM so it blinks the following message in code:
>"Warning
> > to hollowstaters:  Glass envelope contains solid state components which
>may
> > be offensive to your sensibilities.  This message in compliance with
>Truthi
> > in Thermionic Emissions Act of 2002."  If you use more than one of 
>these,
> > they must be synched.
> >
> > Seriously though -- I'm interested in your tube cutting technique.  
>Handy
>to
> > make up 7 and 9 pin plugs out of bad tubes.
> >
> > Barry
> >
> > _______________________________________________
> > R-390 mailing list
> > [email protected]
> > http://mailman.qth.net/mailman/listinfo/r-390
>
>_______________________________________________
>R-390 mailing list
>[email protected]
>http://mailman.qth.net/mailman/listinfo/r-390

_________________________________________________________________
MSN Photos is the easiest way to share and print your photos: 
http://photos.msn.com/support/worldwide.aspx