QUESTION: tungsten needles

[blacknwhite]

Has anyone started re-manufacturing straight-shank tungsten 78 rpm needles yet?

Thanks,
- Bob

[JohnM]

Not that I'm aware, but if that is your inclination, please do!!!

[OrthoFan]

I know that a few collectors are toying with the idea, but I don't know how far it's gotten.

For instance: http://www.phonoland.com/viewtopic.php?f=7&t=2741

Related: http://www.phonoland.com/viewtopic.php?f=7&t=1849

[blacknwhite]

I know that a few collectors are toying with the idea, but I don't know how far it's gotten.

For instance: http://www.phonoland.com/viewtopic.php?f=7&t=2741

Related: http://www.phonoland.com/viewtopic.php?f=7&t=1849

AWESOME, thanks for the links - KNEW someone else had to be experimenting.

Seems the key would be in automating the process.

The hard part there would be, once the stock rod is cut to needle lengths and filed down to a sharp point, actually SHAPING the point to a smooth 3-mil SPHERICAL tip... would require some very clever methods of designing small machinery to do that automatically, while remaining "on a shoestring hobbyist's budget"... Would be fun to try and make the economics of it "work" to be able to sell them $1 apiece...

Hopefully someone else will break down and do it before I break down and do it , ha

[gregbogantz]

I, too, make my own tungsten needles and can confirm some of the observations of others who also make them. I am a collector of old record changers, and there is no substitute for tungsten needles in the early changers that track at 100 grams or more. I've tried various mounting methods for putting the tungsten wire in the shanks, but I have yet to come up with something that is sufficiently easy to do that I would consider making these with the intention of selling them. It is quite understandable that Victor had significant special tooling created for the manufacture of these needles.

Regarding wire size: the original Victor "Tungstone" brand needles use wire that measures 0.0063 to 0.0065 inches or 6.3 to 6.5 mils in diameter. It turns out that this is what is marketed today as "7 mil" wire. I have used "5", "6", and "7" mil wire sizes, with the smaller sizes also actually being a few ten thousands smaller than their stated sizes. The 7 mil wire performs about the same as the original Victor product. You need to use this large wire to prevent the wire from bending under the heavy tracking force of Victor orthophonic or Columbia VivaTonal (#15) reproducers. But this large diameter is actually too big to properly fit into the 78rpm shellac grooves which are typically around 5.5 to 6.5 mils wide at the top. The 7 mil wire works because the heavy tracking force causes it to stay in contact with the groove even though the wire is forming small shoulders as it wears at the top edge of the groove. The "6 mil" size wire (actually about 5.5 mil) is a much better fit and produces less distortion from mistracking, but this wire will bend pretty easily in the typical 150 gram tracking force reproducer. But if you have a lighter tracking force application like, say, an improved early electrical pickup, the 6 mil wire works well. The "5 mil" wire (actually about 4.5 mil) is the best fit for the typical groove size, but it is just too delicate for use with acoustic reproducers and will bend almost immediately.

The issue of forming the playing end of the wire into a spherical shape prior to using it is moot. It's not necessary. The wire quickly wears into the shape of the groove within about one minute of play. The best way to implement homemade tungsten needles is to play about a minute or two of some junk record with a fresh needle. The tip will wear into the shape of the groove and then you are ready to use the needle on your better records without fear of gouging them. Just as Victor suggests, once you mount a tungsten needle, you should leave it in position until it is worn out. If you remove the needle, you need to reform its tip if you remount it by playing a junk record just as if you were starting with a fresh needle.

I'm going to share a little secret about tungsten wire that I haven't heard anybody discuss anywhere yet. Tungsten as it is drawn and hammered into the fine shape of this small wire acquires a crystalline structure which is is longitudinal with the length of the wire. In other words, it posesses a threadlike crystalline structure. It very much matters HOW you cut this wire to the desired length. If you "nip" the wire with conventional wire nippers, you smash the wire at the cut edge which exposes and frays the crystal threads. This breaks the bonds between the crystal threads farther up the wire. This causes the wire to fray and shatter as you play records with it. Which causes breakage and very rapid wear of the wire in the needle. The best way to cut tungsten wire is to grind it, then snap it where you want the break to be. This is very difficult to do with such fine wire. A second-best way is to SHEAR the wire with cutting shears, rather than wire nippers. This can also result in some fraying of the threads, but it is about the best practical way to handle this fine wire. Tungsten is harder than any steel used in typical metal shears, so shearing the wire tends to nick and dull your shears. The proper kind of shear for this purpose would, itself, have to be made of tungsten or something harder like tungsten-carbide or diamond. If you make your own needles, you may notice that some wear much longer than others. This is probably because you frayed the threads more on the needle which wore faster. This is a difficult and unpredictable part of making these needles by hand. I don't know how Victor cut the wire to reliably produce unfrayed threads, but you can bet that they had to give some special thought to this part of the manufacture.

[Brad]

I, too, make my own tungsten needles ..... I've tried various mounting methods for putting the tungsten wire in the shanks, but I have yet to come up with something that is sufficiently easy to do that I would consider making these with the intention of selling them.

Greg,

Have you tried hypodermic needle stock as a shank?

[gregbogantz]

Hi Brad, Yes, I have tried several types of metal tubing as shank material. The basic problem is mounting the wire into the shank securely so that it doesn't slip inside the shank and/or rattle and buzz. I have several methods that work, but none that I would consider putting into production. Victor essentially staked the wire into the shank. I assume this was done with special die tooling that enabled the shank to be cold-formed around the wire, probably with a single stroke from a forming die. All well and good if you've got the wherewithall to make up the tooling.

By the way, I have read elsewhere that the Tungstone shanks were made of brass. That's not correct - they are steel. They are gold plated or gold-washed. Steel is desirable for this purpose for its strength and stiffness. But I have settled on aluminum tubing for my purposes because I can form it more easily, even though the aluminum flexes more than the steel. This flexure causes the needles to have a softer tone than the steel shanks produce. That's fine by me as I prefer soft-tone steel needles anyway. You can make the needles louder by making the shanks shorter if you want that performance.

[blacknwhite]

Greg, thanks for all the info. Fascinating about the internal structure of the metal.

- Bob