Hi Mark,
I make my own tungsten needles. Your observations are pretty much the
same as my own. The original Victor Tungstones were made from wire that
measures about 0.0065 inch or 6.5 mils in diameter. Today, that wire size
is marketed as "7 mil". Yes, I've made needles with this size wire and they
work OK when used with acoustic reproducers tracking at around 140 grams
such as the Victor orthophonic (#5) and the Columbia VivaTonal #15. Even
though the wire is really too large to accurately fit inside the groove, the
extra width that forms shoulders on the edges of the wire gets ground down
reliably due to the heavy tracking force. But when used in lighter force
reproducers such as the Victor Exhibition or #2, the tracking force is
sufficiently lower (80 to 100 grams) that the needles tend to rattle and
distort because the shoulders of the wire are not being ground off reliably.
So, I tend to prefer the "6 mil" wire (actually about 5.5 mil) as it fits
the groove better and can be used with these lighter tracking force
applications. But you are correct in noting that the 6 mil is noticeably
more inclined to bending than the 7 mil. I'm sure that Victor used the 7
mil wire because of this very need for robustness. I've also tried "5 mil"
diameter (actually around 4.5 mil), but that is just too flimsy to be
useable in anything tracking at more than about 40 grams or so.
I don't know if the annealing process is the same as that used in the
original Tungstones. But I've obtained tungsten wire from several sources,
including SmallParts, and it all behaves about the same way. So I'm
guessing that annealed wire is probably the only kind that is sold.
As I commented on the Talking Machine Forum recently, HOW you cut the
wire has a LOT to do with how long it lasts as a needle. As the tungsten is
hammered and drawn into the fine wire shape, it's structure becomes that of
elongated crystalline threads. If you cut the wire by nipping with
conventional wire nippers (diagonal cutters), you smash the crystal threads
at the cut which significantly reduces their strength. The proper way to
cut tungsten wire would be to grind it, then snap it. That is very hard to
do with wire this fine, but you can probably use a Dremel tool with a cutoff
grinding disc. The next best method is to SHEAR the wire. This does not
smash the crystal threads nearly as much as nipping the wire. If you have
experienced variable playback longevity with your needles, this may be the
reason: the wires with the frayed crystals will break and fray quickly
which reduces the needle life. The problem with shearing this wire is that
you really need a shear made with VERY hard blades as you are cutting
tungsten which is the hardest metallic element. Using a shear with tungsten
carbide blades would be the most practical solution. Using an ordinary pair
of shears with hardened steel blades works, but the blades will be nicked
and banged up pretty quickly. That's what I've been doing, but I'm aware
that I'm abusing my shears. Oh well, it's all for a good cause.
Greg Bogantz
----- Original Message -----
From: "mark french" <[email protected]>
To: <[email protected]>
Sent: Tuesday, February 16, 2010 7:58 AM
Subject: [Phono-L] Tungsten needle questions
I was looking at a thread from last year that included talking about some
collectors making
their own tungsten needles ("Victor vs. Columbia big guns"). I've been
making my own needles too for use in my Victrola 10-50, the big acoustic
machine with the auto changer.
I wanted to bounce off what I'm using to everybody and see if I am ok with
what I'm using...
maybe not ideal, but at the least, ok. I'm using .006" wire from
SmallParts.com, it comes in
straight 5-foot long pieces. However, in the specs on the website, it
says 'Temper -
Annealed'.
There was a mention about annealed wire being too weak for use as needle
tips.
I have been using my needles for many months now, and as long as I make
sure I don't
go overboard with the length of the tungsten tip, I am not having
significant problems with
the wire tips being too weak. Since they have thinner wire than the
factory "Tonofone"
needles I have, which I measured at .007", I make sure that my .006" tips
are somewhat
shorter than those. There is also the factor that since I can make as
many of these as I
want for only about 2 cents each, I can afford to make the tips as short
as I want.
I mean I don't need them to last 50-100 records like a Tungstone - just
enough to be able
to play 2 or 3 or 4 12-record stacks.
Anyway - comments/suggestions? Would annealed vs. not really make a
significant difference
in strength in this application? Smallparts was the only place I could
find to buy a small
amount of this size wire. I compromised with .006" wire, since .007" is
too big and .005 was
the next size available and it just won't take the weight.
Thanks!
Mark French
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