Magnetic turntable bearing

[YNWOAN]

It also depends on the specific strength of the magnetic field and how much this field is compressed.

[deduikertjes]

I tried one disc magnet on the chassis and several discs at the underside of the platter

How do you attach the discs to the underside of the platter and how do you achieve sufficient precision?
Can you please provide us with photographs?
Marco

[sq225917]

Something like this

http://www.vinylengine.com/phpBB2/al...hp?pic_id=6163

[deduikertjes]

Something like this http://www.vinylengine.com/phpBB2/a...php?pic_id=6163

Please elaborate a bit on how you did get it centred with sufficient precision.

And what magnet is on the other side. A ring magnet? How did you get that one centred precisely?

MArco

[YNWOAN]

Hello Marco,

I was not sure who you were asking about construction methods so I did not want to interupt before (I hope you don't mind now).

I designed and built the particular magnetic bearing that sq225917 has built a version of, and describes. We know each other well and I hope he agrees with this.

The bearing I use has one large ring element and another element consisting of a circular, ring, array of cylinder magnets. I built a number of prototypes before arriving at my final realisation (five prototypes).

I used a CNC Router to produce the supporting structure as geometric accuracy is extremely important for this type of design, Initally I used acrylic but my final design is from HIPS.

Below are a few pictures of the first prototype that I built. Sorry, but I do not have any pics of the final design. In the photographs the bearing consists of two circular arrays of cylinder magnets but (as said before) the final design replaced the lower array with a single ring magnet. In addition, the increased magnetic field of the later ring magnet allowed me to use much fewer cylinder magnets for the top most array. The construction methods are largely similar between prototypes though.

[deduikertjes]

Ynwoan,

Thank you. Now I understand.

From the picture in http://www.vinylengine.com/phpBB2/a...php?pic_id=6163 I got the impression that you managed to find a method which didn't involve CNC routing. Unfortunately that is not the case ...

I'm afraid I have to be clever al by myself.

Marco

[YNWOAN]

Hi Marco,

I'm glad if I helped a little. I'm afraid I'm not sure which pic you are referring to as the link you have provided does not go to any specific picture (this may be because I have deleted many of my old posts from vinylengine).

In actual fact the ring magnet I use essentially has a CNC machined spacer to locate it concentrically with regard to the main bearing and this could be made by hand (carefully). In addition, it is possible to recreate much of my work without access to CNC equipment (it's just more difficult). Accuracy is important though - bear that in mind and have fun.

[Triumph]

Clearaudio does it with two simple magnets. I also think it is possible with two strong ringmagnets. See post #115 + 122. This is simple to make (without CNC work??). Problem with my attempt was a worn out and to short sliding bearing. I used a Garrard which I modified now to a fully satisfying inverted ceramic-steel bearing. So the magnetic bearing is no longer needed. But it was an interesting project tough.

[deduikertjes]

I also think it is possible with two strong ringmagnets

I've tried with 2 loudspeaker compensation magnets. These happened to be way to weak, so i want to replace one of them with a super magnet. As to my knowledge super ring magnets aren't sold, I have to make a ring with smaller ring magnets.

MArco
(in this thread you can see the turntable I'm working on: scrapyard turntable

[K.A.B]

Originally posted by deduikertjes


As to my knowledge super ring magnets aren't sold, I have to make a ring with smaller ring magnets.

[/URL]

http://www.neotexx.com/ have neo rings up to 50mm or 2"

Anders