[quote quote=“ToddSimpson” post=11361]What is an acceptable range of particle size for these products?
It seems to me that a small percentage of oversize particles would dominate the polishing behaviour.
I’d also like to thank you for posting the link to these photos. They’re amazing, and I’ve created my new account here in order to properly express my appreciation (…and Hello! to all here). 
David
Hello and Welcome!
[quote quote=“ToddSimpson” post=11361]What is an acceptable range of particle size for these products?
It seems to me that a small percentage of oversize particles would dominate the polishing behaviour.
Someone in another forum tracked down the source of the photos… “fuzzy chops” in a shaving forum. Here’s a link to one of the threads…
http://www.artisanshaving.org/viewtopic.php?f=11&t=1340
Cool stuff! :woohoo:
Welcome to the forum Todd! Thanks for the link.
Happy to share these images.
I have been experimenting with (straight razor) stropping and just acquired some diamond spray to try.
There are a few images of 0.5 micron and 0.25 micron monocrystalline diamond spray here:
diamond spray micrographs
[quote quote=“ToddSimpson” post=11361]What is an acceptable range of particle size for these products?
It seems to me that a small percentage of oversize particles would dominate the polishing behaviour.
That depends on the product.
Ken Schwartz did a series of three articles on this subject.
Here is a link to part 1:
http://precisesharpening.blogspot.com/2010/12/part-1-comparison-of-three-quarter.html
part 2:
http://precisesharpening.blogspot.com/2011/01/part-2a-comparison-of-three-quarter.html
Part 3:
http://precisesharpening.blogspot.com/2011/01/cbn-cubic-boron-nitride-scanning.html
According to his comparisons, and SEM nanographs (I like that term…) there can be a wide range of particle sizes. Better products have tighter controls on the range of sizes.
The last SEM images you linked are great stuff, but it is not mentioned what product is being imaged.
Phil, If you hover over the images a title will pop up. I think these are all Hand American sprays.
Got it…
I saw the HA in the titles… did not make the association.
Thanks!
I can tell you that paper, such as plain old notebook paper, can polish metals. Working at a paper manufacturing plant I see many spots on the machines where the paper has polished the surface where it rides on the plates and some are mirror like. Granted, the machine surfaces are not hardened to a high RC but the paper is abrasive enough to cut into the metal. I have wondered about and seen where some have tried stropping with materials other than leather and pastes so the diamond sprays may be overkill. I don’t know.
It seems that those larger particles do leave visible scratches, but there is no effect on the edge.
Shapton 8k
Shapton 8k followed by 10 laps on 0.25 micron diamond spray
Is that 10 laps with .25m spray on leather?
Interesting pictures… thanks!
2" English Bridle strop
Pretty much an impossible concept for me to grasp. If the particles are leaving scratches, they will effect the edge… unless you are simply not hitting the edge during stropping.
How can those particles be selective in where they leave scratches on their own??
I’d have to agree. It seems like the micrographs are of excellent quality, but the honing technique is not convincing. And the concept that coarse particles have no effect on an edge simply is not accurate. If it were true, we would simply have one grit size. Am I missing something in the discussion?
I’d also agree that paper alone has abrasive properties. And that different papers have different properties, from coarse papers, to extremely fine writing papers. This is a larger topic in terms of what are suitable substrates for various grits.
Ken
There are a couple of observations that may help.
First, this is a straight razor edge, so there should be a single bevel of angle around 16.5 degrees.
After the Shapton 8k, the bevel is indeed 16.5 degrees and extends all the way to the apex and there is an edge width of between 100 and 200nm. There is no convexity.
After only 10 passes on the 0.25 micron diamond, the last 10 microns of the edge is convexed (or micro-convex) and a there is a thin foil edge remaining. The edge width is around 100nm where the foil is broken away.
After another 90 passes, the foil is mostly gone; however, there is little additional steel removed (compared to 10 passes). The edge width is around 50nm. The micro-convexing action occurs within a very few laps, and from there is edge shape is “stable”
The depth of the scratches is much less than the size of the grit. The 0.25 scratches are 10 or 20 nm deep. The “deep” scratch from the “large” particle shown in this image is no more than 100nm deep; however, it does not extend to the apex. I would speculate that because of the micro-convexity, the scratch ends a few microns from the apex - in other words the apex is above the plane of the bevel and the “large” particle does not touch this last few microns.
The percentage of “large” particles is not very high, so there are very few of these “deep” scratches. If large means 1 micron and deep means 100nm.