Chosera stone maintenance
- This topic has 112 replies, 13 voices, and was last updated 08/08/2013 at 11:15 pm by
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Awesome, Clay!!
Here’s more surface texture. Up next is the 5K Shapton Pro, using the same lapping methods on the 140,400,600 and 1200 Atomas. Image size is 1mm x .75mm
We can see that the depth of scratch is not nearly as deep as the 8K Shapton was, hinting at a more solid binder (you could also attribute some variation in lapping technique) Note the shape of the clusters, not that it means anything! 😆
The 400 Atoma scratches are very clear and consistent. This is an acceptable grit to lap the stone with and corresponds with the Shapton Diamond Glass Lapping Plate (DGLP), which is approx 325/375 grit.
This is the 600 Atoma. It’s what I personally prefer to use on my 5K. The 5K Pro is a polishing stone which, by definition, could/should use the 1200 Atoma, but because the 5K is the workhorse of the critical leap on the Shapton Pro series, I like it to be slightly more aggressive.
1200 Atoma on the 5K is faintly visible at this magnification. Note how the surface has “craters” of abrasives – this is what Ken S was talking about with greater magnification needed in order to see what was happening at the individual particle level.
I will get some macro level shots at each level to show how what we see on the surface of the stone with our bare eyes corresponds to the micro images. Next up is the 5K Chosera, though.
Here is the 5K Chosera with the #140 Atoma. We can see scratches more clearly than on the 10K – part of this lack of clarity can be attributed to the self cleaning that occurs on the lapping plate – the slurry from the stone actually does build up on the diamond plate a little, and creates a layer of 5K slurry between the diamond and the stone. This happens even faster on the 10K.
The 400 Atoma leaves the surface looking like the moon. the scratches essentially run through clumps of abrasive (which is white). You can see how this makes the stone more aggressive, since it will essentially split the peaks of the mounds, creating more peaks, thus more initial cutting power.
The 600 Atoma leaves the surface relatively smooth at this magnification, and just like the 5K Shapton, is my preferred lapping grit for this stone.
The 1200 leaves the surface very smooth and clean:
I will go back an do a macro set of shots at each grit.
OK this is the last picture progression – sorry for hogging the thread! :whistle:
I’m only putting the 5K Chosera macro pics up because it shows what the scratches actually look like on the stone with more or less the naked eye.
5K Chosera on Atoma 140
5K Chosera on Atoma 400
5K Chosera on Atoma 600
5K Chosera on Atoma 1200
I think we’ve more than proved the point that scratches in the stone surface from texturing do not transfer directly onto the blade, and that you can use texturing to somewhat control the aggression of a stone.
And We’ve opened up a new can of worms about what is really happening at the sub-micron level, which my scope can’t handle… :dry:
I took one of Tom’s pics – the Shapton 5k stone texturized with the 600 grit Atoma – and did a bit of image processing to bring out the scratch pattern a bit more to see the scratches more clearly. I cropped an interesting area of the image – in the right quadrant, the lower left portion of it.
overview:
Cropped closeup image:
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KenStarting next week I should be able to get back into experimentation and microscopic imaging. I’ll be able to texture some stones and then image the effects they have on the metal.
Ah… saved me some typing. 😉
Seems to me, this is what actually matters.
Today I printed a new microscope stage that allows me to adjust the angle of the bevel very precisely in relation to the lens so I can choose to focus on the very edge, bevel or shoulder by adjusting a screw. I’ll eventually get one made at the machine shop but this one is working great for now:
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