220# Stop

M

MadRookie

Joined
Sep 15, 2010
Messages
234
Took my PM2 S90V & decided to do a test edge.

Profiled it to 15 dps with a micro bevel of 17 dps on the EP.

I used Atoma plates for the profiling & only 1 stone....the 220# Shapton Glass for the micro bevel - no mirror, no bling.

Made sure that there was absolutely no burr, using extreme light strokes.

It shaves arm hair in 1 pass and has terrific bite.

The 3 finger Murray Carter test....no ways...my brain refuses to agree.

On the opposite side of the sharpening spectrum I got to say that this "refined" coarse edge really grabs my fancy.

I have used it somewhat and doubt whether I will go with a higher grit again for me personally on my EDC.

Obviously S90V loves a coarse edge....will have to see on some of the other steels....

Some pics:

BEFORE









AFTER



















:)
 
Welcome to the coarse side. We have toothy knives :thumbup:.

From my past experience with having a DMT EF as my highest grit I wasn't as much of a fan of it and I found coarser stones to work better for me. For me I am more of the middle of the road as I find that works best for me so far so the fine side of a norton economy (india or crystolon, I own both what I finish with depends on my intended use) followed by a strop works best from my limited experience. I haven't tried finishing off a knife on a coarser edge yet but I wish I did last night on a family members no name mystery stainless steel fixed blade, it just cut beautifully after the coarse side on the economy crystolon I wish I left it at that than to finish it up on the fine side.
 
Hey MadRookie, Say what? After all those beautiful polished edges you are going to do WHAT? J/K Still nice work though....
 
Just tried stopping at the coarse side on my norton economy (silicon carbide) while reprofiling my practice sharpening knife and did a quick strop and it slices through newspaper in all directions (just barely) and push cuts in certain directions (just barely again). Not bad considering how bad the reprofile job was and it only took me 8min from start to finish. I must admit it was quite satisfying to see that, and it probably shaved a few minutes off me sharpening on the fine side.

Originally wanted to get some practice in on reprofiling a knife at more acute levels and failed at that but decided to strop and give it a shot at my sharpness tests and was impressed as it was more than I expected. This makes me wonder what I can actually do with a more coarse edge if I were to reprofile it properly.
 
Yes, there are many benefits to a coarse edge. Glad to see more gents finding this out. DM
 
I find this to be a bit at odds with logic. I admit that I haven't had the opportunity to examine a large number of scalpels, but a former colleague in the necrology lab showed my perhaps a dozen of his, and their edges were very highly polished and refined.

I think it would be logical to assume that surgeons, pathologists and necrologists use basically the same cutting instruments. If the less refined edge cuts better, why would it not be used on scalpels??

If there is physician on the forum, perhaps you could weigh in on this topic?:confused:
 
From my experience with playing around with coarse to the more refined edges it seems the coarse edges seem to act like micro serrations or saw teeth if you will and work quite well on slicing. My normal task for my knives is opening letters and cardboard duty and I tend to do a more slicing motion for this. Though a happy middle ground works best from my experience so far, so for me the edge I get off an fine india or a slightly toothier one from the fine side of the crystolon stone is what I choose to go with now days. This works for me as I still have a slightly toothy edge but I have some ability to push cut if I choose to do so.

And the more refined edges seem to work better in push cuts. The highest stone I have is the DMT EF and well I can get it to push cut things a lot better such as newspaper and whatever else I throw at it that edge doesn't seem as good for my normal day to day tasks. I have also noticed that even going from coarse to fine on either stone there is a big difference if you were to try to do something like push cut newspaper or shave a few hairs off your arm the more refined edge has an easier time doing it. Same story again going from the crystolon to india the more refined edge is easier to push cut. I imagine this is the reason why people refine edges so much for straight razors as it push cuts easier so it irritates the skin less.

I also find it harder to get a knife sharpened on a coarse stone harder to push cut something like paper but it's not impossible to pull that off. It almost seems like there is a very large amount of skill to get it "just right" so you have some of that ability. Where as the finer stones make it easier to pull off. But this may just be me, it's just what I've experience so far. Neither is superior toothy or polished edges, they both serve their purposes. What I've wrote is what I've experienced so far with playing around with different finishes which is limited to say the least so hopefully someone else can chime in with more detail or any corrections if it's needed.

EDITED IN:

As for why they have refined edges for scalpels they do push cuts. They don't stab into what their cutting and slice outward or inward. Instead they cut into what their cutting as far as needed and push the blade along to cut. The more refined edge works better for that.

If you want to get a better idea of this sharpen up a couple of identical kitchen paring knives and leave them at different finishes. A coarse one and a highly refined one at the very least and cut up newspaper, paper, cardboard, rope, etc you will be able to get a good idea of whats going on. And try doing different things like push cuts and slicing on them. You'll learn to appreciate the differences.
 
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