The Black Hole......

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#2,881
Not as advanced as some of the articles discussed but I've sent a couple of microridge tipped cartridges for imaging by someone I know in CA who has a fancy focus stacking rig. Gives a nice view of the contact point, which in this case is 0.1mil by 0.8 mil. Hoping to solve the question of what the wear limit is for this cut. I suspect that that stylus starts to bottom out in the groove before the laser cut wings wear out.
 

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#2,882
billshurv said:
Not as advanced as some of the articles discussed but I've sent a couple of microridge tipped cartridges for imaging by someone I know in CA who has a fancy focus stacking rig. Gives a nice view of the contact point, which in this case is 0.1mil by 0.8 mil. Hoping to solve the question of what the wear limit is for this cut. I suspect that that stylus starts to bottom out in the groove before the laser cut wings wear out.
Click to expand...

Nice picture, but how to interpret this.
Is the black area to be considered as polished by the groove while playing ?
An image from the frontside would reveal if the tip is still in topshape.

Hans
 
#2,883
Hi Hans,


The method has been developed to get maximum contrast on the actual contact patch which is the black stripe. This works really well with standard cuts but this is the first imaging of a worn microridge. For comparison front vs side of a new elliptical
 

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#2,884
billshurv said:
Hi Hans,


The method has been developed to get maximum contrast on the actual contact patch which is the black stripe. This works really well with standard cuts but this is the first imaging of a worn microridge. For comparison front vs side of a new elliptical
Click to expand...
It is always surprising how a comparatively large rock ending in a super small tip can follow the track of an LP.
It is like landing with a 747 on a small table.
Even more so is the fantastic labour quality to produce this tip as can be seen in your nice pictures, very very smooth.

Hans
 
#2,885
Sadly not my pictures. I just wish I had time and space to setup a rig for this. It's not expensive in real terms I'm just super space constrained. Once again modern camera and PC tech makes it possible to do these things without the budget of Shure brothers!


Ray who did the pictures started off imaging coins and then combined the microscope with his love of vinyl.
 
#2,886
Check this out, all the way down: $10-20 and 0.25 liter of storage volume does it.

Maybe even a jeweller's loupe held against your telephone could do the job; I once fixed leakage problems by finding and polishing scratches in pneumatic valves (scuba regulators) with this technique.
 
#2,887
Zung said:
Check this out, all the way down: $10-20 and 0.25 liter of storage volume does it.

Maybe even a jeweller's loupe held against your telephone could do the job; I once fixed leakage problems by finding and polishing scratches in pneumatic valves (scuba regulators) with this technique.
Click to expand...

With all respect, but the stacked pictures that Bill provided are far superior.

Hans
 
#2,888
I'm just checking it's ok then will post the latest stacked images from Ray. I do daft things for learning sometimes. In this case I bought a worn out ATN150MLx stylus and posted it to California to try and settle an argument.


I've always thought that the microridge stylus would bottom out in the groove before the laser cut wings wore out. Turns out this is exactly what happens.



I should admit at this point that I am a stylus tart and have gone out of my way to collect examples of as many of the extreme stylus profiles as I could find/afford. This is a silly use of time and money which makes it completely compatible with listening to vinyl in the first place 🙂
 

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#2,890
composite images

Here are the composite images from Ray showing how the wings on the diamond wear down until eventually the stylus bottoms out. This should be a 'soft' end of life as it will start to sound awful before it is worn enough to cause damage.
 

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#2,892
#2890 photos are excellent.

SHURE was using a modified microfilm viewer to project on it’s flat screen the shiny and shady reflections of a light source when illuminating a cartridge tip placed below the objective lens of the viewer.
On the flat screen there were pattern lines for spherical, elliptical and super elliptical profiles (Last time I saw it was ~30 years ago). It was very easy to evaluate the condition of a cartridge tip.

George
 
#2,896
billshurv said:
The old optical method was a good ready reckoner. I just love how you can actually measure the size of the contact patch as see how it grows over time. It answers questions that are fun, whilst totally irrelevant in the 21st century.
Click to expand...

Find yourself an old Nikon V12 with DRO:
nikon-metrology-profile-projector-V12B.jpg

You will have hours of fun projecting microscopic details onto a 12" screen! I used one for years to check head profiles during lapping. Most machinists use them for cutting tool profile verification. You print out or draw a large version of what you are trying to achieve on Vellum, then clip it to the screen (clips provided), then project the tool profile and iterate grinding it until it matches the drawing.

Cheers!
Howie
 
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