I decided to check out plain leather again, first top grain horse butt, moistened with distilled water:
and then top grain horse butt dry:
hmmm…
At least our little sedge (or chicken foot) shaped scratch is getting more shallow.
At this point, I was unsatisfied with the polish level and decided to drop back down and repeat the following progression: 1 boron carbide> .5 micron chromium oxide> .25 micron diamond> .125 CBN
I didn’t photo each step, just worked quickly through the progression to get back to .125 microns. Now we’re getting somewhere!
Attachments:
Here is where things get really interesting - I decided that the bevel was polished sufficiently and we’d be able to examine the scratches from the strops in question, so I began a descending progression, starting with the 3.5 micron diamond and top grain leather strops:
Go figure…
The sedge/chicken foot shaped scratch is almost gone.
Descending yet further to the 5 micron diamond and top grain leather strops, stroking in the opposite direction. Note what has happened to our little sedge shaped scratch:
On to the 10 micron diamond and top grain leather strops. We’ve lost our sedge/chicken foot scratch but we now have an odd little hole for reference:
Still alternating strokes so we can see the new scratches clearly.
Finally the 14 micron diamond and top grain leather strops:
Still switching stroke directions.
Climbing back up the ladder, switching stroke direction on each grit:
10 micron diamond and top grain leather strops -
5 micron diamond and top grain leather strops -
3.5 micron diamond and top grain leather strops -
So far so good. More to come.
Now it gets weird again:
1 micron diamond and top grain leather strops (Wicked Edge paste)-
This looks good. Onto the next - .5 micron and top grain leather strops (Hand American spray)-
weird?!? And the next - .25 micron diamond and split grain leather strops (Hand American spray)-
weirder still. Next are the .125 micron CBN and split grain leather strops (Precise Sharpening spray)-
Contamination? Maybe something to do with the split grain leather… My guess is that the top grain leather really does move the metal around the surface and the leather is doing most of the work. With the split grain leather, the diamonds are doing more work than the leather. Lots more testing to be done here!
I decided to go back to the 1 micron diamond paste and top grain leather strops since that was where I had my last, best result:
It was a worthwhile move, the bevel cleaned right up again.
Finally I put a 17° micro bevel on the blade with the 5k Chosera stones. This knife is going to get used, ostensibly for deboning meat, so a slightly toothy, slightly wider micro bevel will be just the thing:
and then I did about 20 strokes per side with the 3.5 micron strops to put a final touch on the edge. I hope Krystina’s customer likes it:
I’d love to hear everyone’s thoughts.
More evidence of what Tom often describes: starting with the 1 micron boron nitride phase, a small dot becomes visible in the middle of the blade about 2/3 of the bevel from the edge. As I continued to polish the bevel, this dot becomes more and more visible, incrementally revealed with each progressive grit. Each step is essentially pealing back the layers of light scattering so we can see the dot better. The same is true of scratches and that is why we suddenly see scratches as we get into the higher grits.
On the next knife I do, I’ll use the stock diamond stones and ceramics before proceeding to the strops.
Excellent, Excellent, Excellent!!! Thank you Clay!:woohoo: :woohoo: :woohoo: :woohoo:
It almost looks as if the .25 and .125 cause more damage, when in reality, they expose everything underneath.
One thing we need to be careful of is all the crisscrossing. I think this is the most difficult type of scratches to remove, and again, at the .25 and especially the .125 levels, it makes everything look “bad”.
One thing Clay or I have not really mentioned is just how sharp these knives really are despite their ugliness under the scope. Sharp is a given.
WHOA Clay! That reveals tons of info I don’t think we ever would have had without looking at the edge on a micron level! That’s wild how the 1 micron diamond paste seemed to polish better than even the .125 CBN spray! That may very well cut out a lot of time on the end polishing of edges for some of us =)I still don’t understand how the 14m paste still seemed to be more refined/higher polished than the 10k chosera (form looking at the pics), that is weird! So I have a few questions…
- How did you get the microscope to the same position each time!? lol, with the stand?
- How many strokes did you do on average per side on each grit?
- Could you explain a little more about the different types of leather grains? (i.e. full, top, and split grain)… I actually purchased this and re-stropped my paddles with the rough side out… what kind of effect do you think this will have? I noticed that the WE strops are smooth side out, but everything I’ve read on forums seems to imply that the rough side should be facing out so it will hold the stropping compound better… what are your thoughts?
Here are a few pics of the leather in the link above… it is supposed to just be cowhide tooling leather… what do you think?
that is what i’m REALLY interested in… basically b/c that’s what I have is stock everything at this point (althoug my 5k/10k chosera’s are coming in tomorrow! lol)… What does the jump from the 1600 ceramic to pasted strops look like? VERY interested to find out!!
Hey, thanks for spending all the time doing this for us… It means a lot that the owner of WE would take the time to do this for his customers. I also know how much time this probably took… Thanks again!!!
[quote quote=“jendeindustries” post=2040]Excellent, Excellent, Excellent!!! Thank you Clay!:woohoo: :woohoo: :woohoo: :woohoo:
It almost looks as if the .25 and .125 cause more damage, when in reality, they expose everything underneath.
One thing we need to be careful of is all the crisscrossing. I think this is the most difficult type of scratches to remove, and again, at the .25 and especially the .125 levels, it makes everything look “bad”.
One thing Clay or I have not really mentioned is just how sharp these knives really are despite their ugliness under the scope. Sharp is a given.[/quote]
So you think that’s what it is Tom? Just the finer micron grit revealing deeper scratches that were already there? Could it not be some cross-contamination or something? I think one thing you could do to be able and tell would be to go to plain leather at that specific stage and see if it clears out the valley that may have had metal pushed into it… what do you think?
The stock progression is definitely next. For the microscope positioning, I leave the scope in the stand. Then I tape photo paper to the bottom of the stand to add some extra light via reflection. I trace the knife’s outline on the paper so I can get it back in the same position every time. As far as smooth/rough on the leather, I like the smooth side out. I did experiment with both styles in this progression and feel that my results with the smooth surface were better. My sense is that the smooth surface, especially when the surface is tacky as with the paste, is able to create enough ‘stiction’ to draw the metal across surface of the bevel, smoothing the peaks and filling the valleys. So far, it’s just a theory, but one I’m working on with some great scientists at the lab. For the time spent, it was about 5 hours total between all the steps and documentation. There were a bunch of calls and emails in the middle of it, so maybe it was a little bit less. All in all, time well spent! I loved doing it and sharing it. As with everyone else on this forum, I love doing little bits here and there to continue learning. There are so many great people here that have taught me a lot! I’m excited to continue exploring this fun world of sharpening with everyone here.
Clay did you sharpen the ‘tang’ (curve up). If not I am curious to know ;-).
Josh - Clay’s progression of pictures shows both cross contamination and revealing scratches.
For example, this 10 micron to 5 micron picture shows 3 distinctly larger scratches in the middle of the edge, which is cross contamination.
But if you watch the .25 to .125 progression, you see a greater contrast of the previous scratches with each finer grit.
The scratches on the left of the .125 could be cross contamination or revelation due to their size. At this point, it’s hard to tell.
A little off topic, but cross contamination of strops is the major reason why I personally prefer to progress as far as possible on stones, even though the polishing power of the pastes and sprays on leather is proving to be much less invasive.
[quote quote=“jendeindustries” post=2045]Josh - Clay’s progression of pictures shows both cross contamination and revealing scratches.
For example, this 10 micron to 5 micron picture shows 3 distinctly larger scratches in the middle of the edge, which is cross contamination.
But if you watch the .25 to .125 progression, you see a greater contrast of the previous scratches with each finer grit.
The scratches on the left of the .125 could be cross contamination or revelation due to their size. At this point, it’s hard to tell.
A little off topic, but cross contamination of strops is the major reason why I personally prefer to progress as far as possible on stones, even though the polishing power of the pastes and sprays on leather is proving to be much less invasive.[/quote]
I agree about contamination between the 10 and 5 micron samples though probably not crossing from one strop to the next, I’m pretty fastidious about the way I handle and store them. Environmental contamination is more likely - those strops traveled with me to the ECCK Show and could have easily picked up some metal filings or a stray diamond in all the melee which is a show environment. Another possible source of contamination is airborne silica - it sounds far fetched but is a reality, more or less so depending on locality.
The .25 and .125 strops were brand new when I started the progression, so contamination there is probably not a factor. One big difference is that I used the split grain side of the leather which seems a lot rougher on the metal. The metal surface was nearly totally smooth when I worked back up to the .25 and .125 grits and the different reference points like the little hole/black dot make it easy to see the new scratches. At this point, I’m inclined to believe that the scratches that appeared with the second pass with the finer grits are a result of the split grain leather. On the first pass with the plain split grain leather, more scratches appeared as well.