Cutting Needle for Wilcox Gay Sr

[tape]

My recently aquired Wilcox Gay Recordio has no cutting needle, only the playback needle. The manual suggest that only a RECORDIOPOINT needle can be used as replacement. A google search for such one results in zero hits.

I hope somebody here might know where to find one.
Or may know if it's possible to make one out of a sewing needle or likewise.

thanks

[grooveguy]

Cutting styli (needles) are a special breed. You should look at an old book on disc recording to get a general idea of the chisel-like shape required to gouge a groove into lacquer or other plastic material. If you are able to heat the end of a sewing needle or old-style steel phonograph needle, you can bend the tip at an angle of 30 degrees or so, giving you something that will emboss, rather than cut, a groove. Not nearly as good, of course, and very difficult to play back because the groove is so shallow.

SOMEONE in this group needs to develop the required skill to grind cutting styli. We are now able to improvise a way around lacquer blanks, but a source for cutting styli remains elusive. For a gemologist, used to grinding facets on jewels, this should be a relatively simple matter, as it might also be for a tool-and-die maker who can do miniature work. Simple and inexpensive styli of tool steel would be welcome despite their limited service life.

[cuttercollector]

I would, again, go to West-tech services.
http://www.west-techservices.com/
Cutting styli are divided along several lines.
Groove size ("standard"78 or microgroove), material (steel or sapphire), and length (short or long shank), plus some of the pro units use specialized heated ones.
Your unit was made to cut 78 non-microgroove records. Though the least durable, you should start out with a steel non-microgroove stylus to experiment with. I think, that your unit uses a typical 5/8" "short shank" stylus. There is what is called a long shank too. It has to do with how far inside the cuttng head you insert it before tightening the screw. Which somewhat influences cutting angle and depth which influences the quality of the groove cut and thus the sound quality.
I am sure Gib will know there at West -Tech if you tell him what it says on the cuttting head. You can then try microgroove or a longer lasting sapphire tip once you get everything working right. (see other discussions)

[Steve E.]

I've decided I'm NOT happy using modern microgroove styli on my recordio. The recordings come out much quieter than I think they should. The angle of the cut is different. They just aren't designed for the job.

I seem to be having better luck with steel! Gonna start sharpening the suckers.

[Steve E.]

I just realized I could have done a better job of answering your question.

Ebay!!

I bought a pair of still-packaged ancient Recordiopoint needles there--just plain old steel ones which will wear out soon, apparently--for, I dunno, $20? I don't remember. They were a little rusty (disclaimered as such) and as of today, they work GREAT. I just recorded a dixieland band called "Loose Marbles" using them today, and I'm very pleased. I mean, this machine never sounds fantastic but it was decent as this thing goes.

[cuttercollector]

About cutting microgroove...
I wonder about the volume difference. If the cutter swings "X" amount for a given voltage input, wouldn't the groove be cut to the same level? A possible explaination is in not cutting as deep you are making a smaller groove with a sharper point, which theoretically at least a smaller overall physical groove with less ability to store energy. Also, the slower you cut, I think that also stores less energy. Perhaps that is why late commercial 78s sound so "hot" level wise with respect to early Lps cut with the same mono heads. Later "hot" stereo Lps of today are cut with 1KW pumped into the head (with feedback) rather than, say, 50W.

[JayDC]

Maybe it's could be a combination of the smaller tip of the microgroove stylus and the cutter armature movement threshold. Could it be possible that the cutter armatures ability to only move so much, could be acting as some sort of mechanical limiter?.

[Steve E.]

I think both of these are distinct possibilities!

[cuttercollector]

Hmm, not smart enough to "do the math" on this but reasoning it out...
First. there is a given amout of amplifier power available before clipping and high distortion set in. Similarly, if the limit of excursion of the cutter is reached, yes it will begin to chop off the top and bottom of the waveform with resulting very high distortion. In a small, low power rig like the recordio, I bet the amp runs out of steam before the cutter "bangs against the stops".
At the other extreme you have the non linearity of the cutter and amp at very low signal levels. This leads to distortion at very low cutting thresholds which may or may not be present and/or get buried in the residual surface noise. A class "A" (single ended) amp can't suffer from crossover distortion at low levels because it is not push pull. The cutter can however suffer from either sticktion as in it does not move at all untill a certain voltage threshold is passed or non liniearity as in wanting to move more easilly in one direction than the other which has to do with internal mechanical alignment. This also causes low level distortion. Both of these conditions are likely to fall below the surface noise level of a typical recording, if everything is operating as it should and so are not much of a factor.
The threshold determined by the noise floor, to the maximum level without severe distortion determines effective dynamic range.

While it is true that a certain amount of voltage applied results in a certain amount of cutter movement or volume cut, the actual current across the load impedance of the cutter (which will vary slightly with frequency, groove depth, stylus sharpness, lacquer hardness etc.) determines the "work" done. Not enough available instantaneous current from the amp translates to higher distortion and less over all level (the voltage sags)

There is a certain amount of power to overcome a certain amount of resistance (actual cutting "work" done) If you are cutting a smaller shallower micro groove, you art doing less "work", (probably lower peak current demand on the amp because of less actual chip being cut and so not as low of a cutter impedance) but there is less energy retained in the finished grove product. Hence, less available energy on playback. That is to say, lower volume level.

It's all derivations of ohms law really. There is just voltage (variable with the audio signal) across a load resistance (the cutter - more or less fixed load, but see above) whose combination results in a draw of a certain amount of current. which translates to a given number of watts of power.
Increase the voltage across the load and the current and power go up, untill something reaches it's limit.

A note about "0".
When the vu meter says "0" at the edge of the red or in our little home cutters the neon bulb flashes or the little green eye closes all the way, that indicates only that the system has reached the maximum level the manufcturer decided the system was capable of cutting at without severe distortion. That level varies with different machines. It varies with speed.
It varies with groove size. It is not the same as one of the pro standards of "X" centimeters per second = "0" recorded level that have been established on a professional level. Modern high power lathes are capable of blowing those standards away - cutting much hotter that can be tracked faithfully by most cartridges. Our home machines with their small non-feedback cutters and 2-20 watts of power can't achieve those levels,
no matter what the meter indicates it's doing.

[OLDLEE]

You can indeed grind your own cutting needles, using old 78 RPM extra-loud phono needles. One uses a high-speed Dremel tool or equivalent fitted with a very fine-grain grinding wheel. First the shank flat is ground on, then on the opposite side the point of the needle is flattened and then the 45-degree grinds are made on each side. The rear surface is then ground at a steeper angle, perhaps 60 degrees. Examine the needle point under a very powerful magnifying glass to verify accuracy and sharpness of the cutting edges. I usually re-temper the needle afterwards to get back to the required hardness.