Is it possible that a stylus will wear to a sharper point?

[sean sweeney]

Been checking out some of my stylus is here, as I have several turntables, and I like newer styluses and keep everything up to date. I occasionally will look at them through a little scope I have to check out the tips and the overall shape.
One thing I seem to have noticed is that good turntables will wear a needle in a much different fashion. Maybe I'm crazy and maybe I'm just imagining these things but it seems as though the better the turntable is the more likely that the needle will get more pointed but keep its General shape. On the left is a brand new stylus that hasn't been played at all. On the right is a Pickering from the mid to late '60s that has had some play, but likely in a nice turntable that tracks lightly. In fact it may have had thousands of hours for all I know but the turntable I pulled it from was a rather nice Garrard that tracked lightly for the day.
Is this something that's already more or less assumed or proven?

 

[mr_petit]

Eventually the stylus will wear into a 45deg point when the wear surfaces on each side will touch.
At that point your stylus runs in the bottom of the groove and you immediately have to change it as it will cause record damage as the stylus won't run anymore 100% on the groove walls (and thus won't have sufficient stylus pressure there)
This will cause distortion and record wear.

From above this looks something like this, where you can see both wearpatches on the side touch (quite badly here...)

 

[Blue Shadow]

Sparky's Fabulous DIY Stylus Microscope

Such a humble title, don’t you think? After the interest shown concerning my initial thread titled “Stylus Microscopes”, and the general unavailability of used Shure SEK-2 stylus microscopes, I decided to try a DIY stylus microscope project. The thought is that dedicated DIY’ers can build an...

audiokarma.org

this thread talks about how to see wear on a stylus.

 

[Buck Rogers]

Yes, The needle wears to a point at which time it scrapes the bottom of the groove and bounces back and forth against the groove walls taking chunks out of the Vinyl.

Sumiko Blue Point Special with logged 3700 hours of play the stylus has been riding bottom for so long it formed a "screwdriver" shaped contact patch. The flat part of the tip is so wide that the SRA can be accurately measured, at 96deg. There is significant imbalance between the contact patch wear, with left contact much more worn than right, but it was played on an air-bearing Linear Tracking arm so the imbalance was presumably not caused by Anti Skate forces.

The contact lengths are very long, 0.93 mil and 0.78 mil, about 3x the max length for full FR reproduction. I can't imagine this cartridge sounded very good, and it may have done a lot of damage to the records it played.

I made the composite image below with tip shot by ringlight. I also took the image with the Shure method and will include it below. The Shure image does not show the extremely close contacts as they appear in the front view for some reason, but I am including it for completeness. It certainly shows the large/long contacts.

 

[egellings]

My impression of a worn stylus is that it will have a sharp edge or edges at the boundaries of the wear pattern, and those edges will act as chisels to damage the record grooves.

 

[cafe latte]

Been checking out some of my stylus is here, as I have several turntables, and I like newer styluses and keep everything up to date. I occasionally will look at them through a little scope I have to check out the tips and the overall shape.
One thing I seem to have noticed is that good turntables will wear a needle in a much different fashion. Maybe I'm crazy and maybe I'm just imagining these things but it seems as though the better the turntable is the more likely that the needle will get more pointed but keep its General shape. On the left is a brand new stylus that hasn't been played at all. On the right is a Pickering from the mid to late '60s that has had some play, but likely in a nice turntable that tracks lightly. In fact it may have had thousands of hours for all I know but the turntable I pulled it from was a rather nice Garrard that tracked lightly for the day.
Is this something that's already more or less assumed or proven?

Yes eventually wear patches meet.
Re stylus life, at 2g a conical lasts maybe 400 hours, and elliptical lasts 300 hours a Shibata lasts 600 hours and a micro ridge 800 to 1000 hours.
I have seen several stylus with big hours from customers. One 3x30um recently with 2000 hours which showed unbelievable wear. The minor radius was massive and it had been bottoming out for a very long time ( see the pic) the other was a micro ridge which had done 1800 hours at 1.8g.
The ridges were gone and it has worn well into the shoulders and again it had been bottoming for a long time.
Chris

 

[cafe latte]

New for comparison

 

[sound hound]

On the right is a Pickering from the mid to late '60s that has had some play, but likely in a nice turntable that tracks lightly. In fact it may have had thousands of hours for all I know...

From your picture, it looks like the stylus may have been gouging out the vinyl on the records. There appear to be a lot of chunks of something on the stylus, probably including chunks of vinyl. With a diamond being harder than the vinyl, it would seem that the wear to a record would be heavier than the wear to the stylus. I would think that by the time the stylus becomes more pointed, it has already done extensive damage to records.

 

[SONDEKNZ]

I honestly can't see anything much in this photo.

Educate me, please.

 

[sean sweeney]

From your picture, it looks like the stylus may have been gouging out the vinyl on the records. There appear to be a lot of chunks of something on the stylus, probably including chunks of vinyl. With a diamond being harder than the vinyl, it would seem that the wear to a record would be heavier than the wear to the stylus. I would think that by the time the stylus becomes more pointed, it has already done extensive damage to records.

I never used it, i was just curious.

 

[Buck Rogers]

The "FLATS" you see in these pictures are the actual point of contact or point of Wear between the Needle and LP record groove walls.

The bigger they are the lower in the groove the needle sits and the worse the tracking or ability for the needle to follow the squiggly groove walls.

 

[Ken Boyd]

I would say you want to change the stylus before it ever gets to the point that the flats merge.

 

[loudnoises]

I often wish for the days where stylus scopes were plentiful. I expect vevor will have something within a year or two though. They sure caught on with the record cleaning quickly. But after a few years of wearing out styli, I don't question my ears when they tell me it's done. Especially if you run multiple tables, you'll notice when one starts sounding wrong.

If friction is a function of force, say you've got a stylus that tracks 1.5-3g. Will running it at 1.5g give you twice as much time before it wears to the same dullness? Somebody must have put it to a legit test?

 

[cafe latte]

I often wish for the days where stylus scopes were plentiful. I expect vevor will have something within a year or two though. They sure caught on with the record cleaning quickly. But after a few years of wearing out styli, I don't question my ears when they tell me it's done. Especially if you run multiple tables, you'll notice when one starts sounding wrong.

If friction is a function of force, say you've got a stylus that tracks 1.5-3g. Will running it at 1.5g give you twice as much time before it wears to the same dullness? Somebody must have put it to a legit test?

There is a graph somewhere, wear increases exponentially then flattens out which is odd.
Chris

 

[loudnoises]

There is a graph somewhere, wear increases exponentially then flattens out which is odd.
Chris

I dug for a bit but couldn't find that graph. But I did dig up some interesting writings on the subject.

https://pspatialaudio.com/stylus_wear.htm

the difference in wear between shapes is fascinating. Off the cuff it seems to say that a nice light tracking conical will cause the least damage to the groove.

 

[lini]

I dug for a bit but couldn't find that graph

There are two graphs plus a bit of additional info in Shure's good old technical seminar paper (2nd section, figure 17 & 18), which you can find there: https://service.shure.com/s/article...technical-seminar?language=en_US&region=en-US

Greetings from Munich!

Manfred / lini

 

[sean sweeney]

There is a graph somewhere, wear increases exponentially then flattens out which is odd.
Chris

I would say that perhaps it's something as simple as the cantilever or glue coming into contact and not being hard or brittle, it doesn't wear like the diamond, and absorbs enough force for it to extend the life of a likely terrible stylus by that time.

 

[cafe latte]

I would say that perhaps it's something as simple as the cantilever or glue coming into contact and not being hard or brittle, it doesn't wear like the diamond, and absorbs enough force for it to extend the life of a likely terrible stylus by that time.

No it's not that, Shure i think did the study, wear was exponential then after a point the increase tracking force made less effect.
That said I retipped an elliptical SPU that tracks at 4.5g, it only had 60 hours and the stylus was very worn.
Chris

 

[sound hound]

I would think that as the stylus becomes worn, there is a greater surface area that comes in contact with the vinyl. Wouldn't the pressure then become less, as the tracking force is spread over a larger area?

 

[cafe latte]

I would think that as the stylus becomes worn, there is a greater surface area that comes in contact with the vinyl. Wouldn't the pressure then become less, as the tracking force is spread over a larger area?

Yes, but no, as the stylus wears the minor radius gets bigger and the stylus can bounce around the groove increasing wear.
Chris