When you wanna go low grit... How low should you go?

HwangJino said:
Hmm, my misono has a super polished edge via 8000 grit kitayama stone and it goes through red meat fish and proteins as if it werent there.

I have a 400 grit stone and that is for tip fixing or worst case senario re profiling entire blade road.

1000 is the norm for low grit.
Click to expand...

While I agree with you because I sharpen hundreds of kitchen knives every week you must remember folders are a different world. A 8k edge on a folder will not perform the same as it does on a Misono.
 
Yep, mostly because we aren't working with cuts of meat and fish. Nylon rope, heavy duty plastic film, and cardboard are my folder's main diet.
 
This sounds petty perhaps, but I have been carrying a coarse edge this week and while it is very sharp, I do not care for it with *my* cutting style.

As a push cutter, I like to cut the ears off these cardboard display boxes with a straight pull (and a small knife). The coarse edge loads up with fibers and starts binding. (Yes, it is still hair popping sharp at all points along the blade).

By comparison, my polished edge will hiss through box after box with little effort.

Different strokes...
 
Absolutely :) My cutting style is usually with the blade at a low angle of attack, 20-45 degrees to give the most slicing action, and I try to use as much of the blade length as I can by sweeping from heel to tip.
 
KennyB said:
Actually part of the reason behind why I started this thread was because I was debating with myself whether to get a DMT coarse credit card sharpener, or a DMT extra fine credit card sharpener, so I figured I'd hear people's views on toothier edges.
Click to expand...

For what it's worth, I've been living very comfortably with my DMT Fine & EF 'credit card' hones for a while. I'd picked them up at a local woodworking outlet (which now, unfortunately, has closed up shop), and would've also grabbed a Coarse if they'd had it at the time (they didn't). I've yet to get the Coarse, and likely will when it's convenient. But, depending on what steels you may sharpen, it's possible it won't be as necessary or useful as the Fine/EF combo. I have other DMT hones in Coarse grit at home (2 C/F Dia-Folds, 1 8" C/F Duo-Sharp, and 6" double-sided Dia-Sharps in XC/C & F/EF), and don't use the Coarse nearly as often as the higher grits. Softer and less wear-resistant steels more easily take a toothy edge with a relatively finer diamond grit, so I've seldom felt the need to use the Coarse on them.


David
 
unit said:
This sounds petty perhaps, but I have been carrying a coarse edge this week and while it is very sharp, I do not care for it with *my* cutting style.

As a push cutter, I like to cut the ears off these cardboard display boxes with a straight pull (and a small knife). The coarse edge loads up with fibers and starts binding. (Yes, it is still hair popping sharp at all points along the blade).

By comparison, my polished edge will hiss through box after box with little effort.

Different strokes...
Click to expand...

:thumbup:
A polished finish on the bevels makes a huge difference on cardboard, especially with thicker blades. A thinned & polished convex on an otherwise relatively thick blade is almost scary in how it zips through heavy cardboard, and with minimal accumulation of fibers/adhesive binders along the edge (assuming the edge is really clean & crisp).


David
 
Obsessed with Edges said:
For what it's worth, I've been living very comfortably with my DMT Fine & EF 'credit card' hones for a while. I'd picked them up at a local woodworking outlet (which now, unfortunately, has closed up shop), and would've also grabbed a Coarse if they'd had it at the time (they didn't). I've yet to get the Coarse, and likely will when it's convenient. But, depending on what steels you may sharpen, it's possible it won't be as necessary or useful as the Fine/EF combo. I have other DMT hones in Coarse grit at home (2 C/F Dia-Folds, 1 8" C/F Duo-Sharp, and 6" double-sided Dia-Sharps in XC/C & F/EF), and don't use the Coarse nearly as often as the higher grits. Softer and less wear-resistant steels more easily take a toothy edge with a relatively finer diamond grit, so I've seldom felt the need to use the Coarse on them.

David
Click to expand...

I was originally carrying the F/XF cards, but now I carry the C/F. But that's mostly because I take the stones with me everywhere I go, and I come across dull knives which I'll sharpen on the spot. As 99.9% of the knives I sharpen are in bad shape, I save myself a lot of time with the coarse diamonds. Finish with the fine card and strop with my DLT field hone loaded with BR green compound.
 
Fascinating thread here guys. Now I know why the few polished edges I have work so much better on cardboard than the toothy edges I have.
 
Coarse edge = more friction = better draw cutting. Polished edge = less friction = better pressure cutting/chopping. If you do enough tests you'll get a very good feel for what works better for a given application.

Mentioned this before, but this test in particular really drove it home for me. High polished 3.25" edge on a folding knife chopped through a branch of green ash approx 3/4" with one hit. A coarse edge barely chopped past the bark and was stopped within 1/8", even with a draw. Same knives on free hanging canvas, using only the belly of the blade (no digging in the tip) and the polished edge couldn't even get started - coarse edge parted it like a curtain. Likewise the coarse edge drew through sisal with noticeably less pressure. Different edges mate up with different materials, find the right fit and function you'll get tremendous results not only in performance, but longevity. IMHO, for max versatility an edge in the 600-800 grit range (1200-2000 JIS) will give best performance.
 
Why then do I see so many people chasing after the mirror polished edge?
That reminds me, I just sharpened a kitchen knife that I had a similar experience with. I used my (newly flattened) Lansky benchstone both the coarse then the fine side when I finished with the fine side I stropped it on the fine side and on a copy paper strop wrapped around the stone. That knife was hair popping sharp. I used it to chop up about 9 potatoes yesterday and it would still shave. I was impressed by that edge.
 
How low should you go? Depends on what you mostly cut. An edge coming of a x-coarse diamond stone will cut a lot of sisal rope before needing a touch up. Normally for general purpose cutting I take my edges to 320-325 grit. This level will cut most material well and give good edge retention. DM
 
Squashfan said:
Why then do I see so many people chasing after the mirror polished edge?
That reminds me, I just sharpened a kitchen knife that I had a similar experience with. I used my (newly flattened) Lansky benchstone both the coarse then the fine side when I finished with the fine side I stropped it on the fine side and on a copy paper strop wrapped around the stone. That knife was hair popping sharp. I used it to chop up about 9 potatoes yesterday and it would still shave. I was impressed by that edge.
Click to expand...


Aside from some woodworking tools where you might want that sort of edge, I think it's just for the thrill of seeking that elusive thing called "perfection" If you ever see a mirror polished edge from an edgepro or similar sharpener, I think you'll understand. Now, putting them on the knives you use every day I don't really see the practicality of, but the way a properly refined mirror edge can push cut is indeed a thing of wonder.
 
a mirror polish on a scandi grind or convex that will be used for woodcraft is very good. A mirror polish on an axe is good, too. I guess for wood, the more glass-like the final edge, the better. I don't see it as valuable for a kitchen knife, but maybe a pocket knife depending on your needs.
 
Don't get me wrong. I would put a mirror edge one of my knives if I could but I don't think it would make a good choice for my carry knives. I cut plastic straps, cardboard and plastic bags. And the occasional sandwich.
I am still not good enough with sharpening to create different kinds of edges. I am just grateful when I get my knife sharp enough to cut the above stuff.
 
You must log in or register to reply here.
Back
Top