Thank you, Greg!
Are you saying that tungsten wire shaped needles are just clipped
lengths of tungsten wire, without a point being formed on them before
being used to play a record?
Chris
Greg Bogantz wrote:
Osmium tipped needles were a transitional style. They were the
cheapest "permanent" needle typically marketed in the late 1930s thru
the '50s. The more expensive varieties of "permanent" needles were
sapphire or ruby and the most expensive were diamond. People were
using record changers and didn't want to mess around with changing
steel needles all the time, so these styles became popular. The
problem with all of these needles in that time period is that the
pickups tracked at too high a force for any of them to be optimal with
regard to record wear. The magnetic and crystal pickups of that
period typically tracked at between 30 and 80 grams. Although that's
less than the 80 to 150 grams of the earlier acoustic reproducer
period, it's still just too high for any of these hard needles. They
were especially deadly when used with the early vinyl 78s that were
beginning to appear after WWII. The proper technology for high
tracking forces was the steel or tungsten wire needle when used with
shellac records that contained abrasive fillers that were intended to
quickly wear the needle into conformance with the groove shape. But,
of course, the steel needles needed to be changed with every record
side or two. Tungsten WIRE shaped needles are superior to the osmium
tipped needles because the cylindrical wire shape retains the same
cross-sectional area during the entire lifetime of the needle. The
osmium needles were tapered and as they wore they got a bigger cross
section. This is fine until the cross section gets too big to fit
into the groove width which happens after just a few records are
played. Then the needle forms shoulders that ride outside the groove
and on the land of the record. This lifts the needle out of close
contact with the groove walls which leads to mistracking, distortion,
and high record wear. These hard needles, especially the sapphire and
diamond ones don't wear down quickly, and instead wear the records.
These needles that were typical in this time period are the main
reason that records that have survived from the '30s thru the '50s
look worn and sound more distorted and worn than records that have
survived from the teens and '20s and that were played properly with
steel or tungsten wire needles. The use of these hard needles only
became proper when pickup tracking forces were reduced to 10 grams or
less in the 1950s. I don't feel comfortable using them even above
about 5 grams. Tracking forces of 1 to 2 grams became commonplace in
the early 1960s, and jewel-tipped needles are perfectly satisfactory
when used in these pickups.
The bottom line is, I would NOT recommend using hard needles in any
pickup tracking at more than 10 grams if you want to preserve your
records. When new, these needles will sound good for a while. But
they will be grinding the bejeezus out of your records if you are
tracking them at 30 grams or more. If you have a jukebox or record
changer that operates at high tracking force, use tungsten wire
needles. Or change the pickup (and tonearm if necessary) to allow
tracking forces below 10 grams if you want to use jewel-tipped
needles. Osmium would also work in this application, but it will wear
out after 20 sides or so, even at this tracking force. Osmium is just
a bad idea for just about any application.
Greg Bogantz
----- Original Message ----- From: "Chris Kocsis" <chris...@cox.net>
To: <phono-l@oldcrank.org>
Sent: Wednesday, March 10, 2010 8:47 PM
Subject: [Phono-L] Coin machine or jukebox needles?
Can anyone give me the lowdown on jukebox needles? I bought some new
old stock Cole's coin machine needles with osmium tips. The package
says the needle lasts many plays and doesn't have to be rotated. I'm
also curious about the shape of the needle. A couple of millimeters
up from the point, the metal is flattened into a pointed oval like a
cobra head and then resumes being cylindrical. What is that for?
Osmium is nearly as hard as tungsten and I've seen some references to
people cutting their own needles from tungsten wire and forming the
point by rubbing the cut end in a record groove while rotating it
(which seems astonishing).
Is such hardness a good idea in a needle, or does it cause excessive
record wear?
If these jukebox needles are safe to use, how do I tell when it's
time to change one?
Best regards,
Chris
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