On Tue, 20 Mar 2018 12:25:58 -0400, Frank Krygowski
wrote:

On 3/20/2018 2:25 AM, John B. wrote:
On Mon, 19 Mar 2018 22:43:37 -0700, Jeff Liebermann
wrote:

On Tue, 20 Mar 2018 10:59:44 +0700, John B.
wrote:

On Mon, 19 Mar 2018 19:48:03 -0700, Jeff Liebermann
wrote:

Incidentally, sharpening all my kitchen knives to an edge sharp enough
for shaving was NOT a good idea. I'm cutting myself quite often and
am slowly destroying my cutting boards and dishes. Paper plates no
longer work as my knives cut through the paper.

I don't do kitchen work but periodically my wife hands me a bunch of
kitchen knives and says "Sharpen them". Generally these are cheap
stainless knives and I've found that simply making a pass across a
grinding wheel on each side works pretty well. It produces a sharp
edge which is not perfectly smooth, more like a very fine tooth saw
which seems to cut better then a perfectly smooth blade.

Disclaimer: I am a beginner on knife making but am learning fast.

It depends one what and how you're using the knife to cut. If you
draw the knife as if you were sawing through the food, a rough edge is
quite superior to a razor sharp edge. However, if you're pushing your
way through the food with the knife, the razor edge works better.

What I did was buy about 15 assorted knives at a local outdoor flea
market and 10 more at a local thrift shop. I used these for practice
to learn how to sharpen them and how to modify the shape of the blade.
Most were stainless but I also found a few 1095 high carbon steel "Old
Hickory" knives.
https://www.knivesplus.com/OLD-HICKORY-KNIVES.HTML

I bought a Harbor Freight 1x30 belt sander and belt assortment from 80
grit to 800 grit:
https://www.harborfreight.com/power-tools/sanders/1-in-x-30-in-belt-sander-60543.html
an angle guide:
https://www.amazon.com/Knife-Sharpening-Angle-Guide-Sharpen/dp/B01HVXFP80
and a collection of whetstones:
https://www.ebay.com/itm/Japanese-Whetstone-Knife-Grit-1000-8000-Sharpener-Sharpening-Water-Stone-Stand/222660726466
I also setup a binocular microscope so I could see what I was doing to
the edge:
http://www.learnbydestroying.com/jeffl/pics/microscopes/Olympus%20SZ30/slides/SZ30-01.html
After a few frustrating failures, I determined that I could produce a
usable but rough edge with the belt sander, and then refine it to a
razor sharp edge with the water stones. The sanding might only take a
few minutes on the belt sander, but the water stone polishing can
easily take hours. I can easily see the difference with the
microscope.

I have 6" grinder, but I would not use it to sharpen knives. It takes
off too much metal too quickly to maintain control. When I tried it,
the result was a rather "wavy" edge. Even a belt sander takes off too
much metal if you use a rough (80 or 120 grit) belt. If you have a
belt sander, try starting with 120 grit to remove the dings and chips.
Then use increasingly finer belts until you get to 400 or 800 grit.
You can probably just quit there, or if you want a smooth edge, use a
succession of water stones (1000 to 3000) to improve on the edge.

Somewhere around the Net is a site that talks about super sharp, or
deadly sharp, or some other fancy name. That guy used plain old emery
paper on a flat block to sharpen a knife.

I've tried it and it works pretty well except that if you move the
blade forward - leading with the sharp edge - it scrapes the abrasive
off the paper :-) But it does work pretty well if you pull the blade
"backward" with the sharp edge trailing. I usually have a couple pf
wood blocks with emery paper glued to one side laying around the
bench.

After trying many techniques over the decades, my favorite tool for
sharpening knives is a steel block whose top surface is impregnated with
industrial diamond abrasive. It seems to last forever, which for
practical purposes means it stays flat. I have other whetstones that
have gradually gotten concave, which makes it tough to maintain the
proper edge angles.

I use the classic technique, which is sharpen the main bevel at
something like 20 degrees, then lightly sharpen a smaller bevel at 45
degrees, and touch up or polish the edge with a hone or other piece of
hard steel. I use the hone far more often than the abrasive. Lots of
times, the edge just needs touching up, not actual grinding.

But the emery paper and wooden block are so cheap :-)

The various angles required to arrive at a cutting edge are very
dependent on the use to which the cutting device is to be put.
--
Cheers,

John B.