Narrow-Bandwidth Television Association

Yesterday I've got a new scanning-disc made by a friend of mine. It is made from aluminium, very thin, but not wobbling. Unfortunally the laser in his company is too weak to make real holes, but he marked them on the disk by laser, so I just have to drill them using a Dremel.

The disc is 30 cm in diameter, of course 32 lines club-standard, with synch-holes on an inner ring, like the disks from Peter. In the center there is not only a center-hole, but he made a cross of 4 extra-holes in order to connect it properly.
I'm afraid it is impossible to see the holes on the picture, my camera is not good enough...

Is it interesting for the club to get Nipkow-discs without "real" holes? The advantage of these disks would be the price...

DrZarkov wrote:Yesterday I've got a new scanning-disc made by a friend of mine. It is made from aluminium, very thin, but not wobbling. Unfortunally the laser in his company is too weak to make real holes, but he marked them on the disk by laser, so I just have to drill them using a Dremel.

Is it interesting for the club to get Nipkow-discs without "real" holes? The advantage of these disks would be the price...

I'm new to NBTV but.......
The hole position is THE key to a good picture. Trying to drill out holes just by hand seems to me a non starter.
Even if they are accurately marked out to start with, one would have to centre punch them first using an eye glass. (unless the laser has indented the metal well) So, maybe errors here, especially for the inexperienced to the centre punch technique of 'pulling,' to correct error.
Even then, the tiny drill could wander if only hand held.

Good luck if you do it. I suggest that maybe the small driller be held in a pillar drill stand. This at least will ensure that the tiny drill approaches the Nipkow disc exactly at right angles.

One really needs a good positioning system using a vernier or lead screw or large templates with drill jig bush guidance or a positioned punch. Both under tight control.
Albert.

My first thoughts were -- why not switch to a material other than aluminium, that the laser CAN cut? I've attached an image that I've intensified tp try and see the holes. A bit more detail is evident.

Yes, we did so! The friend of mine was yesterday testing some other materials, he told that he had now much better results. I will know more tomorrow. As I understood him, the new disc is still aluminium, but another sort of, and he did something with the machines. I don't know now any details, he was on his mobile telephone, so I just have to wait until tomorrow...

Today I spoke my friend again, of course they will have true holes, but wiht the current machines no disc will be like the other, they are automatically drilled, so the diameter of the holes will only be "about" 0,7 mm. But he will check to use the laser of another company, so even square holes will be possible, of course with exact diameters. The costs, if we take between 10 and 50 discs will be something about 10 EUR.

And I've infected him, too! He started today to make his own NBTV monitor!

Well done Dr.Z

Another member for the NBTV fraternity.

Regards,

GL