Stylus Evaluation Imaging

the thin end of the wedge
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BlazingArrow74
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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 03:53

ripblade wrote:
15 Jan 2019 03:45
Thanks for these excellent stylus portraits, Ray. This is very illuminating. :D
Agreed.

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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 04:23

ray_parkhurst wrote:
28 Jan 2017 22:51
Along with the N110HE NEO SAS/S, I bought a standard N110HE from JICO. Here it is, using a slightly different configuration. Rather than showing both contact surfaces simultaneously by reflecting light off both sides, I have placed the cartridge in a jig that holds it at 45-deg. This puts one contact surface planar to the camera sensor. By using a ring light, the light "encircles" the contact surface, which appears as a dark area encircled by the reflected ringlight.

Unfortunately, this technique requires two images rather than one. I have spliced the two images together in the composite below.

The new stylus is showing unequal contact areas Left/Right, but I expect that as the stylus begins to wear, the actual contact areas will grow slightly to encompass the whole polished area of the tip and will become more equal.

http://i943.photobucket.com/albums/ad27 ... 20LR_A.jpg
Are these contact areas convex or concave ?

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Re: Stylus Evaluation Imaging

Post by ray_parkhurst » 15 Jan 2019 05:38

They are convex, similar to what is shown in the diagram for the MicroRidge, but with a smaller bearing radius.

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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 05:41

I'm not sure the circled areas are dust in this case. Looks like it could be damage --- tiny gouges, perhaps ? Might explain why I hear buzzing distortion despite being less worn than stylus "2", overall ?
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Re: Stylus Evaluation Imaging

Post by ray_parkhurst » 15 Jan 2019 05:44

I think they are both pieces of dust, but neither of them would contact the groove anyway.

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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 06:03

Do I understand this correctly ?
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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 06:09

ray_parkhurst wrote:
15 Jan 2019 05:38
They are convex, similar to what is shown in the diagram for the MicroRidge, but with a smaller bearing radius.
Light Bulb moment. Thanks, Ray.

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Re: Stylus Evaluation Imaging

Post by ray_parkhurst » 15 Jan 2019 06:18

BlazingArrow74 wrote:
15 Jan 2019 06:03
Do I understand this correctly ?
Not quite. Biggest isue is the yellow circle. That is way up on the stylus, outside the contact/bearing region. The original radius is more where your pink circle shows. The wear has flattened the radius to "infinity".

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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 06:50

So ... I came across this article. I only understand 20% or so of what's here, but shoot me if there isn't applicable information. Cantilevers are even mentioned !

https://www.nature.com/articles/srep36972

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Re: Stylus Evaluation Imaging

Post by ray_parkhurst » 15 Jan 2019 18:12

I shot Stylus 2 with the Shure technique, using a deep focus stack (114 images at 4um step) which shows the whole stylus, epoxy attach, and end of cantilever very nicely. It also confirms this stylus/cantilever is significantly rotated and thi is what is causing the asymmetric wear pattern.

http://i943.photobucket.com/albums/ad27 ... us-2AA.jpg

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Re: Stylus Evaluation Imaging

Post by fscl » 15 Jan 2019 19:08

=D> =D> =D> Beautiful

Thank you Ray and image contributors to this topic.

Diamond p**n...... :oops: :wink: :)

Have accumulated staging, microscope(s), lighting, etc via 2nd hand sources. Topic has inspired me to get better shots up...... [-o<

Fred

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Re: Stylus Evaluation Imaging

Post by BlazingArrow74 » 15 Jan 2019 19:29

Wow. Looks like it's rotated toward the inner part of the groove (left channel). This is the one (of the two) with the skewed cantilever ! I wonder if the skew intensified over time due to this wear pattern. Seems like maybe an azimuth adjustment could possibly compensate for this.

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Re: Stylus Evaluation Imaging

Post by ripblade » 15 Jan 2019 19:52

I wonder, are the V magnets rotated as well? This would be easier to see than the actual tip.

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Re: Stylus Evaluation Imaging

Post by ray_parkhurst » 15 Jan 2019 19:58

ripblade wrote:
15 Jan 2019 19:52
I wonder, are the V magnets rotated as well? This would be easier to see than the actual tip.
Yes, they are. Seems the entire cantilever assembly might have been built properly, but improperly assembled into the stylus body.

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Re: Stylus Evaluation Imaging

Post by ripblade » 15 Jan 2019 20:02

Unfortunate. I've read reports of this kind of thing happening with the MLX stylus. Technically fixable maybe, but not after the fact...

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