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

[farmersplow]

Measuring the cut grooves of the Ortofon test disc:

I use the Ortofon test disc for a few measurements.

First a picture with the microscope (silent cut):
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99_07 ortofon microscope.JPG

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Then the observation and measurement on the PC. The measurement result of the cut width is 95.2µm. This results in a cutting depth of 47.6µm:
Unfortunately, I have chosen a very small font size for the dimensions in this picture. Therefore it is difficult to see.
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99_08 ortofon mess.png

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Here is an image with the microscope (Square Wave duty Cycle 3:7):
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99_09 ortofon microscope.JPG

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Then the observation and measurement on the PC. The measurement result of the cutting width is 93µm. This results in a cutting depth of 46.5µm. The groove spacing is 200µm (127 lpi):
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99_10 ortofon mess.png

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And another picture of the Ortofon disc with the microscope:
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99_11 ortofon microscope.JPG

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Then the observation and measurement on the PC. The measurement result of the cutting width is 87.6µm. This results in a cutting depth of 43.8µm. The groove spacing is 200µm (127 lpi):
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99_12 ortofon mess.png

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To be continued:

Greetings from Austria
Thomas

[zdenek]

In fact, it may be. It seems that you can measure the width without any problem.

[farmersplow]

I think it's high time to report again:

A few months have passed since I last reported. It has been an exhausting time in which a lot has happened and I have also been able to make a lot of progress on the project.

In addition to the thousands of hours of work and development on my lathe, I had to deepen my knowledge of programming microcontrollers, develop new circuit diagrams and PCBs and complete a master's course for mechatronics engineers.

So unfortunately I didn't have much time to write, but now I would like to report on how the work has progressed.

A lot of time has been spent on something that has been on my mind for years. It was about transforming the hundreds of wire connections on my large ‘breadboard’ into a circuit diagram and a PCB. At the same time, other ideas were to be realised or improved.

Here's a souvenir picture of my wire chaos and an idea of my headache:
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MB_01.jpg

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So after a few weeks of developing circuit diagrams and PCB planning, I was able to produce three new circuit boards. Of course the main board (which replaces the tangle of cables), an electrically isolated board for controlling the heating lamps and a new (better) board for controlling the input panel and display:
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MB_02.jpg

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Greetings from Austria
Thomas

[farmersplow]

The electronic control of my lathe:

Once the circuit boards were finished, I just had to fit them with the components:
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MB_03.jpg

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I integrated a variable groove depth control on this main board....
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MB_04.jpg

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...and a groove control.
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MB_05.jpg

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This automatic variable groove control consists of an analogue audio part for signal processing and an adapter board that I planned to be interchangeable for development purposes. Finally, it is controlled by a microcontroller. This allowed me to work on it until I achieved the best result. But I will report on this later.

Greetings from Austria
Thomas

[misjah]

you don't mess around do you?. great work

[farmersplow]

Farmer to mission-control: it's an honour! Thank you very much - and I want to do it right

[farmersplow]

The base plate of my lathe:

In addition to the circuit boards, the base plate also contains part of the internal cabling:
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MB_06.jpg

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I laid the USB-C cables at the same time to enable subsequent programming (and updating).
The circuit board for controlling the heating lamp was manufactured separately to enable galvanic isolation from the main board and to lay the high-voltage cables in a shielded area. This means that there are no interfering electromagnetic fields in the area of the main board and the audio cables.
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MB_08.jpg

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Greetings from Austria
Thomas

[farmersplow]

The base plate of my lathe:

The underside of the base plate will have a ventilation grille and feet.

However, I still have to change the ventilation grille because the long aluminium bars start to vibrate like the sides of a harp, which could be disturbing in certain frequency ranges.
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MB_09.jpg

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Greetings from Austria
Thomas

[displacedsnail]

You know, Thomas, every so often I come across the download of that video you made, Cutting in the Dark - such a great looking system! I'm excited to see the final result. Are you beginning to feel the end of the build coming? (But let's be serious, which lathe is ever "done," anyway?)

[farmersplow]

You know, Thomas, every so often I come across the download of that video you made, Cutting in the Dark - such a great looking system! I'm excited to see the final result. Are you beginning to feel the end of the build coming? (But let's be serious, which lathe is ever "done," anyway?)

Ha ha! You're right, it never seems to get really finished! My dear wife always asks me the same question: “Do you have the feeling that it will be finished soon?” After four years, I can say yes, I have that feeling. I've been saying that for two years, but now it's quite strong - the feeling. I think I'm on the verge of finishing.

[farmersplow]

The marriage.

In car manufacturing, we called it a marriage when the lower part of the chassis was joined to the engine and the body.

In my case, it is the connection of the base plate, including the entire electronic control system, with the lathe.

I had to build a temporary lift for this because the lathe is quite heavy and can't be lifted easily.
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MB_11.jpg

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But this made it quite easy to screw the base plate in place.

In the end, all the electronics are now installed and the many wires that had been causing me headaches for so long are finally off the table.

As already mentioned, I have laid the USB-C cables to enable subsequent programming. I first attached the connection sockets for three microcontrollers to the front. This gives me easy access for updates or programme improvements.
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MB_12.jpg

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Greetings from Austria
Thomas

[zdenek]

will there be a lathe for sale?

when will we hear the recordings because that is the most important thing, said a German poet: the method is not important, the important thing is that it is effective, so when?

[farmersplow]

will there be a lathe for sale?

when will we hear the recordings because that is the most important thing, said a German poet: the method is not important, the important thing is that it is effective, so when?

While we are on the subject of proverbs, I would like to refer to one that has had a profound meaning for over 2500 years:
"The way is the goal". It emphasizes that the experiences, efforts, struggles and developments on the way to the goal are just as important as reaching the goal itself.
The recordings will come soon, just be patient. I wish for patience too, and as soon as possible!