Re: Twiddlesticks

On Wed, 18 Jun 2025 18:03:03 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Wed, 18 Jun 2025 18:04:29 +0100, Cursitor Doom <cd@notformail.com>
wrote:
>

Gentlemen,
>
Many of us are familiar with the all-too-common problem of reciever
re-alignment. Dealing the vintage radios with fragile ferite cores in
their IF stages is unavoidable and can prove to be a major PITA. The
cores are brittle and eager to shatter at anything much above mm/mg
torque levels. The key is to use a tool which is not only non-metallic
but also a perfect fit for the slot it must engage with in the top of
the core. Given the range of sizes one encounters in this concern,
it's often necessary to 'roll your own' tool. Well I have a suggestion
to make. Wood makes the best tool for this job and opinions vary as to
which particular wood is ideally suited to this task. Lemon and orange
are often cited. But they're expensive and hard to source typically.
However, I've found a marvellous alternative: yellow heart. I don't
know what the technical name is for this wood, but that's what it's
informally called. It's cheaper and more readily obtainable than
orange or lemon and AFAIC, *better* than either with it's incredibly
fine grain and viceral hardness. It files and sands readily and when
dipped in cellulose sealer, will not fray in use.
Just thought I'd share that with you guys.
>
CD.

>
I have no experience with lemon or orange wood.  However, if they're
anything like the wooden tuning tools I made and used half a century
ago, I suspect you will have problems.  Wood absorbs moisture from the
air.  I had problems with the tuning changing at VHF (> 100 MHz)

It does absorb moisture if left untreated, yes. That's why it's
important to dip the finished tool in cellulose sanding sealer, wipe
it off, let it dry, then repeat the process. The grain (which is
already very fine and tight with yellow heart) will now be impervious
to atmospheric moisture AND that grain will be bonded by the sealer,
making it much less likely to fray and thereby extending the useful
life of the tool considerably.

frequencies.  This is about half of the tuning tools I've accumulated
over the years:
<https://photos.app.goo.gl/7Gq4r85pipeccUMz9>
>
My favorite do it myself tuning tools are ceramic rods.  Buy some
ceramic rods and grind the tips until they look like a "blade", Allen
wrench, or whatever.
<https://www.ortechceramics.com/products/ceramic-tubes-rods/ceramic-rod/>
>
My 2nd favorite is plastic.  I forgot which plastic worked the best. A
crude  test for a proper plastic is to put a sample in a microwave
oven for maybe 15 seconds.  I just tried it on some of the tuning
tools in my collection.  No heating, melting or fire.  Or, you could
just find a plastic that works as a coil form.
>
If you have a grid dip meter, measure the self resonant frequency of
an inductor and capacitor in parallel.  Find the resonance frequency.
Shove the plastic sample into the core (or nearby).  It should NOT
change the resonant frequency.

Certainly won't ifyou use wood either.