Unfortunately Iain you are not the first person to ask about 'looking after' my prototypes.
I know Les W quite well and am passingly familiar with the Genesis turntable. To implement a magnetic bearing the top plate would have to be re-fashioned and the specific dimensions of the magnetic bearing would have to be re-made to fit the main bearing and sub-platter of your deck - I don't think you would find either of my prototpes to be of much use - also it depends on the weight of your platter.
I know Les W quite well and am passingly familiar with the Genesis turntable. To implement a magnetic bearing the top plate would have to be re-fashioned and the specific dimensions of the magnetic bearing would have to be re-made to fit the main bearing and sub-platter of your deck - I don't think you would find either of my prototpes to be of much use - also it depends on the weight of your platter.
Well, I've made yet another version of the magnetic bearing. This time it uses a large(ish) ring magnet and 20 5mm cylinder magnets. The advantage of this approach is that residual cogging is elliminated. The much smaller number of magnets (20 instead of 40) used in the upper section of the bearing should reduce the magnetic field projected above the bearing and make the shielding even more effective. I've not had a chance to ft or listen to it yet
I'm auditioning a pair of ATC SCM40's o Tue or Wed with a view toreplacing my much loved ES14's
I'm auditioning a pair of ATC SCM40's o Tue or Wed with a view toreplacing my much loved ES14's
I've been very interested in this project and are thinking of doing something similar.
Has to be nice to have your own CNC machine!
I have a few questions about your latest project. How large was the ring magnet you ordered? Do you have any idea roughly how much magnetic force is devoted to repulsion? I understand that you are simply relieveing the bearing of friction, and not floating the platter. How heavy overall if the linn platter with your additions?
If you know the answers to any of these questions I'd sincerely appreciate it!
Thanks
Zach
Has to be nice to have your own CNC machine!
I have a few questions about your latest project. How large was the ring magnet you ordered? Do you have any idea roughly how much magnetic force is devoted to repulsion? I understand that you are simply relieveing the bearing of friction, and not floating the platter. How heavy overall if the linn platter with your additions?
If you know the answers to any of these questions I'd sincerely appreciate it!
Thanks
Zach
OK Zach, here are a few answers which may (or may not) be of help to you:
"How large was the ring magnet you ordered?"
[url]http://www.engconcepts.net/List_Of_Ring_Magnets.asp[/url]
Part R1410, 114.3mm OD, 101.6mm ID, 6.35mm thick. Many thanks to the forum member who posted this link. Plus 20 of the cylinder magnets CYL0350 provide 5mm of lift on the linn platter. Approximately 1mm of lift is still possible with only 10 of the cylinder magnets but the field is much more compliant.
"Do you have any idea roughly how much magnetic force is devoted to repulsion?"
I'm not sure what you mean by this. All of the magnetic force avaliable is radiated all of the time - therefore, all of the force is being devoted to repulsion. Perhaps you mean, what is the strength of the magnetic field? I'm soory but I haven't a clue as to this answer.
"I understand that you are simply relieveing the bearing of friction, and not floating the platter."
No, this is not true. It was never my intention to simply relieve the bearing of friction. The platter is completely lifted clear of the thrust plate although the bearing is still held in allignment by the bearing sleeve.
I've not had a chance to weigh the whole assembly but my Google search tells me that a Linn LP12 platter weighs 3.75KG the magnetic bearing element may bring it a bit closer to 4KG (I'm sure it would support that).
"How large was the ring magnet you ordered?"
[url]http://www.engconcepts.net/List_Of_Ring_Magnets.asp[/url]
Part R1410, 114.3mm OD, 101.6mm ID, 6.35mm thick. Many thanks to the forum member who posted this link. Plus 20 of the cylinder magnets CYL0350 provide 5mm of lift on the linn platter. Approximately 1mm of lift is still possible with only 10 of the cylinder magnets but the field is much more compliant.
"Do you have any idea roughly how much magnetic force is devoted to repulsion?"
I'm not sure what you mean by this. All of the magnetic force avaliable is radiated all of the time - therefore, all of the force is being devoted to repulsion. Perhaps you mean, what is the strength of the magnetic field? I'm soory but I haven't a clue as to this answer.
"I understand that you are simply relieveing the bearing of friction, and not floating the platter."
No, this is not true. It was never my intention to simply relieve the bearing of friction. The platter is completely lifted clear of the thrust plate although the bearing is still held in allignment by the bearing sleeve.
I've not had a chance to weigh the whole assembly but my Google search tells me that a Linn LP12 platter weighs 3.75KG the magnetic bearing element may bring it a bit closer to 4KG (I'm sure it would support that).
Hi YNWOAN. I love your work! Here is what I tried. I bought a bunch of These magnets from parts Express. ( http://www.partsexpress.com:80/pe/showdetl.cfm?Partnumber=329-217 $1.65 ea. X 2) I never thought it would work, but I duck taped one to the plinth of my RM-9 and the other to the underside of the platter. I put the platter back on, and sure enough there was about 5-7mm Clarence. Meaning they raised it up that far. Do to the thickness of them the platter was up to high to play it, (Darn!) but they did work.
Now the platter, magnet, and puck weigh in at 9-10#. Meaning that's how much weight two of them will lift. Another possibility is to stack a few of the magnets on the plinth to support even more weight, if somebody wants to make a heavier platter.
Dave
Now the platter, magnet, and puck weigh in at 9-10#. Meaning that's how much weight two of them will lift. Another possibility is to stack a few of the magnets on the plinth to support even more weight, if somebody wants to make a heavier platter.
Dave
Mission accomplished.
I just completed my magnetic bearing using opposing ring magnets. It took me awhile to find the right strength and magnets that would fit my upper & lower bearing housings. I built my turntable with my own inverted bearing design that worked very well to support the 36 pound platter. I initially used a tungsten carbide thrust plate but I always wanted to relieve the immense force it had to undertake to support the high mass platter. Anyway, that was over a year ago and after searching on & off I finally found a pair of magnets that fit both my criteria.
After building a test fixture and measuring clearance, I was satisfied that machining the pockets and bonding the magnets would be the final test to see if the magnets would perform as I hoped they would.
I initially assembled the lower & upper bearing housings which was a challenge because of the 100 pounds of opposing force generated by the magnets. I had to machine a Delrin sleeve to extend the length of the inverted bearing shaft, after that I assembled both housings and placed the platter on top.
I did this on a granite surface plate so I could place a dial indicator on the platter to measure deviation. The total measured deviation from perfection was 0.1mm, hardly anything to be concerned with.
I then put it to the true test and actually played record after record. What an improvement! Ultra quiet and smooth as silk, well worth all the effort. Below is an image of the lower bearing housing that shows one of the ring magnets bonded to the lower housing. The magnet is nickel plated. Another image shows the complete turntable.
eeka chu said:
I just completed my magnetic bearing using opposing ring magnets. It took me awhile to find the right strength and magnets that would fit my upper & lower bearing housings. I built my turntable with my own inverted bearing design that worked very well to support the 36 pound platter. I initially used a tungsten carbide thrust plate but I always wanted to relieve the immense force it had to undertake to support the high mass platter. Anyway, that was over a year ago and after searching on & off I finally found a pair of magnets that fit both my criteria.
After building a test fixture and measuring clearance, I was satisfied that machining the pockets and bonding the magnets would be the final test to see if the magnets would perform as I hoped they would.
I initially assembled the lower & upper bearing housings which was a challenge because of the 100 pounds of opposing force generated by the magnets. I had to machine a Delrin sleeve to extend the length of the inverted bearing shaft, after that I assembled both housings and placed the platter on top.
I did this on a granite surface plate so I could place a dial indicator on the platter to measure deviation. The total measured deviation from perfection was 0.1mm, hardly anything to be concerned with.
I then put it to the true test and actually played record after record. What an improvement! Ultra quiet and smooth as silk, well worth all the effort. Below is an image of the lower bearing housing that shows one of the ring magnets bonded to the lower housing. The magnet is nickel plated. Another image shows the complete turntable.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Wish I have read this thread before. As Ynwoan mentioned in his first tread:
My experimenting with two neodymium ring magnets (see picture below) failed because of unbalance of the platter, not because off axial forces but of tangential forces of the magnets. Even after honing the sliding bearing to a minimum tolerance the platter has a “tide” of 3 mm.
It must be possible though, see:
http://images.google.nl/imgres?imgurl=http://www.coolgales.com/store/images/ClearaudioMagneticBearing70.jpg&imgrefurl=http://www.coolgales.com/store/cart.php%3Ftarget%3Dcategory%26category_id%3D44&h=45&w=70&sz=3&hl=nl&start=7&tbnid=VV_pvs-iHL5s_M:&tbnh=44&tbnw=68&prev=/images%3Fq%3Dclearaudio%2Bmagnetic%26gbv%3D2%26svnum%3D10%26hl%3Dnl%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:nl
fficial%26sa%3DG
My experimenting with two neodymium ring magnets (see picture below) failed because of unbalance of the platter, not because off axial forces but of tangential forces of the magnets. Even after honing the sliding bearing to a minimum tolerance the platter has a “tide” of 3 mm.
It must be possible though, see:
http://images.google.nl/imgres?imgurl=http://www.coolgales.com/store/images/ClearaudioMagneticBearing70.jpg&imgrefurl=http://www.coolgales.com/store/cart.php%3Ftarget%3Dcategory%26category_id%3D44&h=45&w=70&sz=3&hl=nl&start=7&tbnid=VV_pvs-iHL5s_M:&tbnh=44&tbnw=68&prev=/images%3Fq%3Dclearaudio%2Bmagnetic%26gbv%3D2%26svnum%3D10%26hl%3Dnl%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:nl
fficial%26sa%3DGAttachments
Sorry,
The Clearaudio magnetic bearing link:
http://www.coolgales.com/store/cart.php?target=product&product_id=374&category_id=44
The Clearaudio magnetic bearing link:
http://www.coolgales.com/store/cart.php?target=product&product_id=374&category_id=44
Judging from your thumbnail image, it looks as if the magnets are way too far apart and the platter is also extended too far as well. I can see how you would obtain poor results if that is an accurate picture of what is going on. My magnetic bearing only deviates 0.1mm and that is most likely due to the acrylic platter's imperfection.
Triumph said:Wish I have read this thread before. As Ynwoan mentioned in his first tread:
My experimenting with two neodymium ring magnets (see picture below) failed because of unbalance of the platter, not because off axial forces but of tangential forces of the magnets. Even after honing the sliding bearing to a minimum tolerance the platter has a “tide” of 3 mm.
It must be possible though, see:
http://images.google.nl/imgres?imgurl=http://www.coolgales.com/store/images/ClearaudioMagneticBearing70.jpg&imgrefurl=http://www.coolgales.com/store/cart.php%3Ftarget%3Dcategory%26category_id%3D44&h=45&w=70&sz=3&hl=nl&start=7&tbnid=VV_pvs-iHL5s_M:&tbnh=44&tbnw=68&prev=/images%3Fq%3Dclearaudio%2Bmagnetic%26gbv%3D2%26svnum%3D10%26hl%3Dnl%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:nl
loaded with the platter ynoans magnet only floats the platter by a couple of mm. he uses a LINN bearing so the spindle is sleeved all the way up, hence no increase in lateral play.
this solution doesn't work so well with garrard and lenco style bearing as the spindle is quite short, you would need thin magnets of greater circumference so that they sat outside of the platter stub as shown in your image.
this solution doesn't work so well with garrard and lenco style bearing as the spindle is quite short, you would need thin magnets of greater circumference so that they sat outside of the platter stub as shown in your image.
The picture shows the distance without the weight of the platter. With the platter it is also only a couple of mm.
In a later version a made 3 adjusting screws for leveling the bottom magnet and also a adjusting mechanism for the top magnet but still it couldn’t prevent wobbling of the platter.
Were to order magnets:
http://www.monstermagnete.de/catalog/index.php?cPath=37
In a later version a made 3 adjusting screws for leveling the bottom magnet and also a adjusting mechanism for the top magnet but still it couldn’t prevent wobbling of the platter.
Were to order magnets:
http://www.monstermagnete.de/catalog/index.php?cPath=37
https://supermagnetman.c3.ixwebhosting.com/login.php
a bit further away but he does stronger magnets and more ring sizes.
the 41mm fits a rega platter perfectly.
a bit further away but he does stronger magnets and more ring sizes.
the 41mm fits a rega platter perfectly.
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