The farmer and his plow - When I set out to build a record cutter

[farmersplow]

Exactly, the V-spring has nothing to do with open or closed loop. It is only responsible for positioning the torsion tube at the rear end and should only allow movement in the two +/-45° directions.
Yes, the coils are heavy. That is a disadvantage. And they are not as precise as small coils (in the high-end range). But the advantages are better cooling, higher load capacity and almost indestructible (with a 500mA fuse). I have not destroyed a single coil in a thousand attempts (and I have tried really hard).

[farmersplow]

Cutterhead - light and assembly

Now it's time to assemble the new cutterhead. Before that, I would also like to improve the LED lighting.
I used clear 2K resin for the last LED light. That wasn't so nice. So I made new LED lights and colored the resin milky white before casting.
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It shines much more evenly.

Now I can put the thing together.
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Greetings from Austria
Thomas

[Semar]

What a cuthead, mine is Frankenstein

[Fela Borbone]

Very nice!

[zdenek]

Beautifully !

[farmersplow]

Diamant Stylus

I met an old school colleague by chance. He had been a jeweler and diamond cutter for thirty years. Of course, we immediately got talking about diamond styluses. And YES!!! He wants to try it.

In the meantime, I made a couple of shots from square aluminum.
A few weeks later he gave me three pieces of synthetic CVD diamonds in Neumann style (0.7x0.7). “I'll give it a try” he said.
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First I looked at the tips under the microscope. They look fantastic.
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When Marilyn Monroe sang the song “Diamonds Are the Girls Best Friends”, she wasn't thinking about me

And they fit perfectly into the torsion tube.
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A first “silent cut” test was not so good. A faint grinding noise could be heard. So I gave the diamonds to my friend to polish again. But after another two weeks, he gave them back to me and did nothing. Because he said: “It couldn't be better, it's perfect”.
So I tried again, because I've often heard that it sometimes takes a while for the burin to grind in.
There was a grinding noise, but after 8-10 minutes the noise was gone. The burin is really super quiet. Quieter than the pens I've had so far.
However, I'm not going to start mass production or selling diamond gravers. Despite my friend, the effort and costs are not exactly low and the suppliers on the market make good gravers.

Stylus heating:

Then I experimented with stylus heating. As a test, I wound a heating wire over a wooden toothpick and it quickly charred.

Then I wound the heating wire over an aluminum rod. It is irrelevant whether the aluminum rod conducts, because I wanted to test the glue. The wire gets hot in any case.
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Up to 500mA the wire gets hot and the adhesive holds.
From 700mA the wire starts to glow.
I tested up to 750mA and the adhesive holds.
Here is a video of the test:
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vid 90_09.mp4

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Greetings from Austria
Thomas

[farmersplow]

Diamant Stylus tool

Because I wanted to make it easier for myself to swap the diamond and set it up better, I built myself a small lever. I can now simply twist the stylus and lift it out. The tool also makes it easier for me to set up the diamond correctly during installation by twisting it.
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Greetings from Austria
Thomas

[farmersplow]

Cutterhead - Suction pipe

With regard to the suction tube, I have added another requirement.

On the one hand, I want the suction tube to move with the cutterhead. This is because some panel blanks are so bad that an external suction pipe can graze on “severe” unevenness.
Secondly, the suction pipe should not be positioned laterally but centrally in the middle.

A centrally positioned tube can suck in the cutting thread more easily than a tube positioned at the side.

As a result, the distance to the cutting stylus can be increased and the suction force reduced. This is desirable because high air speeds moving around the cutting graver also leave a low noise in the silent cut.

In addition, a lateral suction tube also “pulls” on the cutting thread from the side. I think that a central suction tube does not have this problem.

Also, the cutting thread can make noise when it strips over the edge of the suction tube.
Therefore, the suction effect should be even and only large enough to ensure that the cutting thread is sucked in well. More suction power only makes more noise.
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Accordingly, I have created such a construction on a trial basis.
Admittedly, this prototype is not yet very pretty, but it works surprisingly well!

Greetings from Austria
Thomas

[diy_cutter]

This suction tube looks great. We are currently using the tube mount on a moving platform and this sometimes creates problems when using blanks of different thicknesses. It requires some adjustment of the tube. In your version, the tube is always in the right place. Good job, Thomas!

[farmersplow]

This suction tube looks great. We are currently using the tube mount on a moving platform and this sometimes creates problems when using blanks of different thicknesses. It requires some adjustment of the tube. In your version, the tube is always in the right place. Good job, Thomas!

That's cool, isn't it? But it doesn't look good yet.

[farmersplow]

Cutterhead - Suction pipe

Anyone who knows me knows that I have to build such a pipe construction better, more stable and more beautiful. It was a bit time-consuming with the parts but I think I can leave it at that. Here are a few pictures of the new suction pipe and what it looks like installed. With this construction the distance to the diamond as well as the distance to the blank surface is adjustable. And the construction is stable enough that the tube does not move when the suction hose is attached and removed.
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Now it looks good!

Greetings from Austria
Thomas

[Thelatheofus]

Now that's sexy ! But I always wondered with this kind of design aren't you afraid that the rubber suction tube pulls slightly on the head as it moves ?

[farmersplow]

You're right, of course. Every advantage also has a disadvantage. Of course, you have to be aware of that. If you consider that the cutterhead should (theoretically) not move, the tractive force of the suction unit will not change. In practice, the cutterhead moves up and down (very little). Hopefully little enough that the pulling force does not change.

On most lathes, the cutterhead also moves over the disc. This also changes the position of the tube. On my lathe, the cutterhead always stays in the same position and the disc moves from left to right. This keeps the tension of the tube constant.

In any case, the hose should be soft.

The problem would not be if the disc blanks were always 100% flat. It can be greatly improved with conical platters or suction system platters.
At the moment I still have to get to grips with this: (see videos)
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Greetings from Austria
Thomas

[farmersplow]

Cutterhead - CH-9 test

I can finally carry out my first tests.

The measured values suggest good results. After closing the loop and calibrating with the feedback compensation amplifier, I ‘only’ had to make a few adjustments with the equalizer.
The white noise characteristic looks very good to me:
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93_01 White Noise Cut CH-9 SALIER with EQ.jpg

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Head assembled.
Suction system connected.
Feedback compensation set.
Volume calibrated.

Here we go!

Here is a video of how I place the Cutterhead CH-9 on the record blank:

93_02 start cut.mp4

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VIDEO - I'm cutting Time - Pink Floyd:

93_04 cut Time.mp4

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VIDEO - I'm cutting Singing Winds - Santana:

93_06 cut singing winds.mp4

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VIDEO - I'm cutting 1,2,3 and The Thrill Is Gone:

93_07 cut 123 and the_thrill_is_gone.mp4

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Here's a video of me cutting the ‘Final Line’ and how the cutterhead automatically unlocks (lifts off) at the end and the turntable backs up:

93_08 cut final line.mp4

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And this is what it looks like when I switch off the light: Cut in the dark!
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VIDEO - Cut in the dark:

93_12 dark cut Battle Without Honor.mp4

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Greetings from Austria
Thomas

[farmersplow]

Cutterhead - CH9 - Audio samples


It turns out that I'm not good at mastering. I can't manage to compress a 100dB original sound to a distortion-free 70dB. And I also need to get better at EQ. But that takes practice and time (like everything else).

I can't remember if I've mentioned it before, but I'd like to make it clear at this point. I have the highest respect for vinyl mastering engineers. I tried for a long time to improve the sound for the cut. But I'm not good enough for that. The time I spent on it was just enough to recognize the big challenge. A good mastering engineer can certainly do it better. My admiration!

Nevertheless, I'm finally happy with the sound this cutting head produces.

Here I finally have a few audio samples.

All tracks were recorded in one continuous track (on a 12’ vinyl disc blank).
33 rpm
No stylus heating
EEQ (monobass) 150Hz
20Hz - 15kHz
Record blank temperature 35°C
Cut Volume 0dB (5cm/sec)
No post-processing!

-Alex M.O.R.P.H. - 4Ever

Alex M.O.R.P.H. - 4Ever.mp3

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-B.B. King - The Thrill Is Gone

B.B. King - The Thrill Is Gone.mp3

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-Bob Walsh - Slightly Hung Over

Bob Walsh - Slightly Hung Over.mp3

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-Grandmaster Flash - The Message

Grandmaster Flash - The Message.mp3

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-Johnny Rivers - Secret Agent Man

Johnny Rivers - Secret Agent Man.mp3

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-Santana - Singing Winds

Santana - Singing Winds.mp3

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-Skrillex - Make It Bun Dem

Skrillex - Make It Bun Dem.mp3

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-Sofía Reyes - 1, 2, 3

Sofía Reyes - 1, 2, 3.mp3

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-The Blue Square - Mama

The Blue Square - Mama.mp3

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-Tomoyasu Hotei - Battle Without Honour Or Humanity

Tomoyasu Hotei - Battle Without Honor Or Humanity.mp3

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What do you think?

Greetings from Austria
Thomas

[zdenek]

the sound [ Battle Without Honour Or Humanity ] is acceptable for duplicates, it is not suitable for mastering and is not suitable for pressing records, as the high tones will drop by a few dB after pressing the record, especially the last track, the mains noise comes from the engine, the frequency response is 10kHz -20dB [it should be at least 0dB ],15kHz is not audible on the analyzer,signal to noise ratio worse than 20 dB for the entire band [needs a minimum of 40 dB], so you can hear that it doesn't blow my ass off....
There seems to be still a lot to do and a long way to good quality, but certainly not with the transducers you used in your head, you can push them out a bit more, but they won't go far.

[zdenek]

spectrum signal for
-Tomoyasu Hotei - Battle Without Honour Or Humanity

[farmersplow]

... but certainly not with the transducers you used in your head, you can push them out a bit more, but they won't go far.

as usual...

[zdenek]

Farmer It's good, there is no tragedy, you can hear it yourself, you need to add capacitors to the motor power supply stabilizer, 50Hz is very audible, or it's vibrations from the vacuum pump
ok! ,it's good, but it should be much better, ok Farmer?

[farmersplow]

...50Hz is very audible...

Motor problem and turntable drive problem have been recognised. Lathe is in progress.