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Old 19th August 2018, 12:43 PM   #1941
nocdplz is offline nocdplz
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Quote, Niffy, they are the best for sure - but with a 90 load why not a ring jewel instead of vees?
c
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Old 19th August 2018, 12:52 PM   #1942
2wice is offline 2wice  South Africa
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Hi niffy, does your pivot and jewels have the same radius?
I thought the idea was to have a smaller radius on the pivot so that there is a point contact.
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Old 19th August 2018, 02:44 PM   #1943
niffy is offline niffy  England
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Quote:
Originally Posted by nocdplz View Post
Quote, Niffy, they are the best for sure - but with a 90 load why not a ring jewel instead of vees?
c
I did a lot of research into the different types of bearings and did look at olives/ring bearings. My conclusions were that Vees still offer lower friction but at the cost of lower maximum load. The vees are self loading so there is no chance of chatter whereas the ring or olive bearings could vibrate against the end stops when used with a horizontal axis, there has to be a little bit of play. Vees are self aligning, as are olives to a lesser extent. Rings need very precise alignment. And maybe most importantly vees offer the best mechanical grounding.

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Hi niffy, does your pivot and jewels have the same radius?
I thought the idea was to have a smaller radius on the pivot so that there is a point contact.
The pivots have a radius of about 0.125mm, the vees have a radius of about 0.25mm. That's actually quite large for this type of bearing. I went for the large size as I was a bit paranoid about bearing wear, I could probably have gone for a smaller radius.

Niffy
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Old 22nd August 2018, 04:16 PM   #1944
nocdplz is offline nocdplz
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Thanks Niffy, surely those who build linear tonearms must have a refined culture for bearings, especially for friction issues. I had bad experiences (low hz discharges) with ball bearings at the beginning, so now my ears are sensitive (or imagine to be) to the chattering, and I try to avoid them as possible.
Like you, with the experience I got the idea that the arms must be "mechanically grounded", that resonances must be absorbed far from the cartrige, never letting them to be reflected backwards: no decoupling, no damping for a clean sound, imho.
Many who know much more than me think the opposite, and build beautiful sounding arms.
For me the problem of jewells is the availability, the industrial cost now does not seem too different from pen nibs.
carlo
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Old 24th August 2018, 05:11 AM   #1945
niffy is offline niffy  England
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Hi Carlo,

It looks like your list of requirements for clean sound pretty much matches mine though I head my list with high rigidity and high bending mode resonate frequency.

Niffy
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Old 9th September 2018, 12:29 AM   #1946
dtut is offline dtut  United States
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This lifter is simple and it does work, but the 3D chess game of getting all the alignments right can be challenging. I can post photos of the parts if anybody wants to try it.
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Old 9th September 2018, 07:01 AM   #1947
carolus is offline carolus  Belgium
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Congrats.
Very basic & (minut)realization
I like it.
Karel
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Old 10th September 2018, 03:40 PM   #1948
nocdplz is offline nocdplz
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Clever, Doug, as usual. Sometimes my Rabbit too feels a little down mood...
Is it there a spring inside? do not understand the role of the metal side rod

carlo
forgot to post this: works fine, easy diying: but pay attention to the fabric hinges (very thin) and glue (white, well diluted)
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Old 15th September 2018, 09:50 PM   #1949
dtut is offline dtut  United States
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Carlo,

That could be built on a kitchen table with an Exacto knife and a little care. And bearing chatter certainly can't be a problem.

The lifter does have a spring. If it were built of metal, which wouldn't be hard, and lubricated with heavy silicone, it would probably self-lower slowly.

The metal rod is there to prevent a small amount of twist as the piston raises and lowers. Better construction might eliminate the need.
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