Strops or stones ?
- This topic has 148 replies, 12 voices, and was last updated 01/05/2017 at 6:27 am by
.
-
- Topics: 14
- Replies: 427
A real revelation to me; is how a paper towel will cause scratches
Wrong. Paper towel with alcohol are needed to remove tiny leftovers crumbles of shaved blade steel. These crumbles are small particles of blade steel itself and they are as hard as blade steel. You need to remove them after each grit. If you don’t remove them, they will do 2 kinds of damage: 1) make scratches, 2) stick on next grit stone and they will scratch badly all knives you sharpen with that contaminated stone. Paper towel does not cause these bad scratches.
Wrong, Wrong.. did you say WRONG???? OH how kind and insensitive… My point ( which you obviously missed )was that using anything to wipe off the blade causes scratches, so why try to (remove all scratches, down to the sub micron, go through all that trouble and time ) when the last thing you do is wipe off the knife???? THAT WAS MY POINT” Wrong indeed
Sorry for my misunderstanding… I was under impression that you wrote that paper towel cause scratches: “A real revelation to me; is how a paper towel will cause scratches”. I need to take English reading classes, English is not my mother’s tongue.
- Topics: 14
- Replies: 427
Yes, Bill. Wrong. The horizontal scratches are caused not by the paper towel but by contaminating grit (either diamond or blade steel) which was wiped along the surface of the bevel and thereby caused a scratch. Normal cutting would not expose the blade to those kind of contaminants. Your logic is based on a certain amount of cynicism. If the blade is going to lose its polish in use, why polish it? Thinking like this, if a blade is going to become dull in use, why sharpen it? The idea is to deliver a mirror polish to the owner, who may choose to simply keep it in his collection display.
That said, I urge you guys to try using a Swiffer duster instead of a rag or paper towel to clean the blade of detritus. There’s literally no abrasive contact with the blade. While the edge is extremely toothy, the Swiffer will leave a few fibrous strands behind. I use it to remove dust for microscope inspection and it seems to work so well that I now depend on it to remove contaminating grits as well. I’d sure like to see what it does at a 2000X magnification, compared to other methods. If it doesn’t clean everything off, maybe I ought to change.
3 users thanked author for this post.
- Topics: 14
- Replies: 427
Question: are the film prices on the site for an entire sheet or just 2 films (one for each paddle)? It doesn’t specify in the description…
The are about 10 (?) films on a sheet. I do about 10-25 knives per film, depending on the steel, the knife length, etc. of course.
Molecule Polishing: my blog about sharpening with the Wicked Edge
1 user thanked author for this post.
Bill, in the practice of real-world sharpening I cannot imagine why you’d want to have an entirely scratch-free blade. So I agree with you that, in that sense, these experiments are rather useless. But I think there are two reasons they are useful:
- Sharpening in general (after getting the first burr) is about – to some extent – wiping out the scratches from the previous grit stone. So if you’re serious about sharpening, it’s interesting to know how efficient stones are in removing the scratches from the previous grit size and how far you can go in this.
- Some people like mirror edges and in those cases you do have to remove nearly all scratches from the previous grit.
Molecule Polishing: my blog about sharpening with the Wicked Edge
I have a couple of reasons for working to create a scratch free bevel:
- By doing so, I learn a lot about how effective different abrasives and techniques are.
- I can use a stone/strop/film on a scratch free bevel and know for certain that the new scratches I’m seeing are only from the stone/strop/film in question. It provides me with a proverbial blank slate and a basis for discussing abrasive properties with people.
- I can set a baseline “point sharpness” for an edge at n° and then compare the “point sharpness” created by other abrasives at the same n°. This tells us something about how effective our various efforts are.
I think the sharpening industry is mostly dominated by anecdotal knowledge and not vigorously studied by science. In the practical sense, all anyone would strive for is “sharp enough” i.e. will the knife cut the things you want to cut. Once you realize that you can go beyond most people’s perception of “sharp enough” a whole world of possibility opens up, but it’s very confusing to navigate because there are so many steels and hardening techniques, blade geometries and finishes, as well as intended uses. You can get on a large number of forums and be told by users of varying experience often very contradictory information about what works best, but their “knowledge” isn’t scientifically validated. These studies are intended to shed some light on the essential question of “which products and techniques will best help me achieve my sharpening goals?” Finding shortcuts between stones or validating a progression of stones for a specific goal is very helpful. An interesting example has come from this study – if’ you’re looking for a mirror polish, the study suggests that the Diamond Lapping Films are the most efficient route to go, but if you’re looking for a single step after the 1000# diamonds, one or more of the ceramic stones might be ideal. Something else I’d like to study in detail is micro-tooth size as it relates to both cutting efficiency and edge retention. Naturally angle selection both of a primary and secondary bevel is also a big factor in edge customization. It would be hard to study these things without a solid foundation of understanding of how the abrasives work together to form a specific edge.
-Clay
Tonight I did a touch-up – well, a little more than a touch-up – on my ZDP Delica. I changed the angle from 20 dps to 19. As my 800’s are pretty warn down, I had to go back to my 600’s. When that seemed to take forever, I stepped back to my new 400’s. I then went through a progression of 600, 800, 1000 and 6 micron diamond film. A couple of observations:
I used edge-leading strokes only – trying to limit or eliminate micro-chipping (toothiness) at the edge. Using my 160X ‘scope the edge looks cleaner than any I’d seen before. I tried the trick of folding a sheet of phonebook paper and standing it on edge. The knife cut it easily and without disturbing the paper, other than leaving a deep slit. This has been easy to do with a really sharp chef’s knife, where the velocity of the edge is quite high, but I wasn’t expecting this result with a short knife.
From the progression, you can see that I tried the 1000-skip-to-6 micron trick. What’s interesting is that the film was already heavily loaded with metal dust. Rather than cleaning the film, I ran 20 strokes per side as they were. On inspection, there was only a trace of scratches left from the 1000 grit diamond stones. The films probably have nearly 20 sharpenings on them. I was already a believer, but wasn’t expecting such performance on a hard steel. This is a test on a very short knife (2.87″), but I thought it would take more work to remove that much steel.
The Grit Comparison Chart in this site lists the 1000 grit diamond stones as 7 microns. If so, then maybe the step to 6 micron is not all that tall. Certainly there’s a bigger difference between them. If the vendor doing the plating is actually using 7 micron diamond media, maybe the end result is something coarser than 7 micron.
AdvancedAbrasives.com lists 1000 grit as being about 18 microns. In any case, I had already benched my ceramic stones in favor of 15/9 micron film. It’s looking like maybe I can retire the 15/9 film as well.
- You must be logged in to reply to this topic.