Author Topic: Knife Sharpening  (Read 3618 times)

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Offline Microdoser

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Knife Sharpening
« on: August 03, 2021, 12:27:14 pm »
Every good cook needs a good sharp knife.

Thought I would start a thread to talk about how you sharpen your knives. I recently downloaded and printed a knife sharpener on my 3D printer. Obviously I bought some aluminium rods and sharpening stones and there was also a couple of bolts needed.

It works fantastically. You print off some angle guides, so you can set it at 0-35 degrees (in 5 degree increments) and go at it.

I can now do the 'tomato on the chopping board, slicing off a paper thin slice without holding the tomato' trick you see on many knife videos. My knives have never been so sharp before. I was even using really cheap aliexpress stones.

What is your favourite way to sharpen, or do you have any tips?
 

Offline radar_macgyver

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Re: Knife Sharpening
« Reply #1 on: August 03, 2021, 12:56:35 pm »
or do you have any tips?
I see what you did there... :)

I get mine professionally sharpened once a year, and use a honing rod before any major prep session.
 

Offline emece67

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Re: Knife Sharpening
« Reply #2 on: August 03, 2021, 01:34:09 pm »
Hi,

I use a KME sharpener (https://www.kmesharp.com/). I use it mainly for (small) folding knives I use as EDC knives, but I have also used it for larger, kitchen, knives. It is not as convenient for big knives, though.

I switched from ceramic and Arkansas stones to diamond ones. Maybe they are not as fine grained as Arkansas can be, but they are definitely much faster. I use progressively shorter sequences of passes over the stone, alternating blade sides, say: 128 passes over one face, switch to the other face for another 128 passes, then switch to the 1st face for 64 more passes, and continue this way down to a single stone pass on each blade face. Depending on the state of the edge I can start with 256, 128 or even 64 passes in case of a fast retouch. Sorry, I always use powers of 2 for this  :-DD I always pass the stone from the heel to the point.

About the angle, over the years I switched from narrow ones (20-25 º, that is 40~50 º total edge angle) to wider ones (30~35 º) as I have found that I do prefer a longer time between sharpening operations over extreme cutting performance. I use a black marker pen to initially adjust the angle: paint the cutting edge in black and pass the stone, too much angle removes the ink at the very edge, a too low one removes the ink near the cheeks, the correct angle removes the ink over all edge length.

The first time I sharpen a knife I reshape its edge to match the sharpener (the KME I own). To do that I adjust the angle using the sharpener marks to the desired one and use coarser stones to remove steel faster. An issue with the KME sharpener is that, if you do not place the knife perfectly leveled on the jaws, you end up with an asymmetric edge, don't ask me how I know  |O  The small size of the KME sharpener does also cause, for big knives, that the blade angle is not constant over the whole blade length (being broader at the center of the blade, as this part of the blade is nearer to the point the stone pivots around). Other sharpeners with different topology (with the stone moving along an axis instead of around a point) maybe be better here. Do you have images of your sharpener?

As steels I do not have a clear winner here. Usual workhorses (420, 440, 8Cr13MoV, …) keep the edge less time, but are easier to sharpen and to get a extremely sharp edge. Other (ZDP189, 154CM, CPMs, …) require more effort to sharp, but keep the edge longer.

Regards.
« Last Edit: August 03, 2021, 02:14:49 pm by emece67 »
Information must flow.
 

Offline deadlylover

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Re: Knife Sharpening
« Reply #3 on: August 03, 2021, 02:28:05 pm »
I recently purchased a Shapton #1000 whetstone and it's been a ton of fun learning/playing with all the cheapie knives I have around the house. At first I was afraid I might cut myself or somehow destroy everything I touch but in reality, it's hard to ruin a knife that's already blunt.  :P

I plan to pick up a Victorinox Fibrox or similar as my first decent knife. I should end it there because I don't need Hattori Hanzo steel to slice an onion....says the guy bookmarking knives for "research purposes only".
 

Offline Microdoser

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Re: Knife Sharpening
« Reply #4 on: August 04, 2021, 12:48:05 am »
or do you have any tips?
I see what you did there... :)

I get mine professionally sharpened once a year, and use a honing rod before any major prep session.

Haha!, It was totally accidental ;)
 

Offline dunkemhigh

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Re: Knife Sharpening
« Reply #5 on: August 05, 2021, 10:32:16 pm »
Oh dear. I fear I am going to let the side down  :scared:

I did the thing with wetstones and guides and stuff but it never really worked out. Finally figured that my favourite chef's knife is a silly angle (not so sharp but last a long time). Trouble is it's my favourite with a really nice balance and decent heft to it.
[attach=1]

So eventually I succumbed and got an AnySharp Plus.
[attach=2]

It works by basically shaving metal off until the angle is correct, so it's pretty brutal (at least until the knife matches). Indeed, one of the demo videos I recall showed rusty garden shears being wiped through just three times and then used to cut paper (edge on, as you do) and tomatoes, etc. But it is magic, and a quick wipe through once a week or so keeps the knife really keen. No visible degradation yet in several years use. And by several I realise I mean nearly a decade.

Sometimes you just need to be pragmatic. I'm there to cut food, not be competition for Japanese katana craftsmen.
 

Offline David Hess

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Re: Knife Sharpening
« Reply #6 on: August 05, 2021, 11:21:26 pm »
In order of when I purchased them, I have:

1. A set of Arkansas stones.
2. A set of DMT stones.
3. A DMT sharpening guide set.
4. Work Sharp Knife & Tool Sharpener Mk.2

I have not used the Arkansas stones in a long time but they work.  The DMT stones are great for larger tools like chisels.  I picked up the Work Sharp Mk.2 for sharpening much larger knives more quickly; I am not completely happy with the edge it produces but the price was right for the capability.
 

Online BrokenYugo

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Re: Knife Sharpening
« Reply #7 on: August 06, 2021, 07:19:38 am »
I use a Lansky kit, doesn't really matter though provided you understand how to do it (raising the burr and whatnot) and can get down to a fairly fine grit, or even go so far as stropping if you want to go all out.

What I find more important is proper use and care, knives don't dull quickly if you use proper cutting boards, dont bang them around, etc.
 

Offline dunkemhigh

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Re: Knife Sharpening
« Reply #8 on: August 06, 2021, 11:37:41 am »
Just in case there's anyone not yet horrified, here's another magic sharpener.
[attach=1]

I haven't used this on kitchen stuff, but just the other day my garage carpet knife needed addressing. Can't remember where I got this knife but it was cheap, the end has broken off (got used for prying, I think) and I use it when I need a really sharp, flexible but ultimately disposable knife. Needless to say, I've had it 20 years or so and it's my go-to knife, so actually losing it would be a Bad Thing.

So, anyway, it was sharp but not really sharp, and my partner asked what the green thing was. Not expecting much, I showed her how it's done with a single wipe on one side, and almost took off my finger when testing the edge!

I think there must be a skill to using the Draper and I just lucked into doing it right on the day.
 

Offline Joel_Dunsmore

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Re: Knife Sharpening
« Reply #9 on: August 06, 2021, 03:55:22 pm »
Harbor Freight 1x30 belt sander.  400 Grit, 1000 Grit and Leather belts.  Lots of YouTube videos on it.  Razor sharp is possible with just a bit of practice.  I hold the knife at a steeper angle than some (about 20 degrees off from the belt, I know others suggest 30).  You can sharpen a half-dozen knives in 5 minutes.
 
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Offline richmit

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Re: Knife Sharpening
« Reply #10 on: August 06, 2021, 06:18:49 pm »
I sharpen everything (kitchen knives, pocket knives, axes, probes, tweezers, scissors, ...) with the Work Sharp Knife & Tool Sharpener Ken Onion Edition:

   https://www.amazon.com/gp/product/B00EJ9CQKA/
 
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Offline dunkemhigh

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Re: Knife Sharpening
« Reply #11 on: August 06, 2021, 06:30:01 pm »
The belts have the convex grind as a benefit. Wonder how important that is - it seems reasonable but sometimes I can be overly credulous :)
 

Offline richmit

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Re: Knife Sharpening
« Reply #12 on: August 06, 2021, 08:34:42 pm »
The belts have the convex grind as a benefit. Wonder how important that is - it seems reasonable but sometimes I can be overly credulous :)

After I switched from stones to belts, the interval between sharpening went up perhaps 50%.  Part of that is because I'm more consistent now, but part of it is probably due to the convex grind. 

The biggest advantage of using something like a belt sander or the work sharp is the speed with which you can sharpen stubborn steel alloys.  I gave up on using stones when I got my first knife with ZDP-189 steel...
 

Offline dunkemhigh

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Re: Knife Sharpening
« Reply #13 on: August 06, 2021, 09:49:57 pm »
Oh dear. I might not be able to resist trying out a belt sharpener. They tend not to be awfully cheap  :palm:
 

Online WattsThat

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Re: Knife Sharpening
« Reply #14 on: August 07, 2021, 01:49:42 am »
Harbor Freight 1x30 belt sander.  400 Grit, 1000 Grit and Leather belts.  Lots of YouTube videos on it.  Razor sharp is possible with just a bit of practice.  I hold the knife at a steeper angle than some (about 20 degrees off from the belt, I know others suggest 30).  You can sharpen a half-dozen knives in 5 minutes.

+1 duplicated here. It’s on the bench, so whenever my wife puts my Wustof’s in the dishwasher, they get the 1000 grit touch up. All are as sharp as when they were purchased and most of my original collection is almost forty years old. Fortunately, my daily users like a small Chef and Santoku are newer so they have the synthetic handles and they do survive the dishwasher treatment.

There is a small learning curve so start on the $10 Dexer Russells or whatever you have - where you don’t mind loosing a little blade width as you experiment with how to hold and angle.
 

Offline Psi

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Re: Knife Sharpening
« Reply #15 on: August 07, 2021, 02:22:06 am »
Do not buy anything that sharpens this way.

Their sharpening surface relies on two angled surfaces to sharpen to a point on each pull through.
This works initially but after a few uses you have ground the angle flat and they are useless.

Note, there are similar angled sharpers which use two independent wheels that rotate, those work fine, it's just the static ones like below which are useless.
« Last Edit: August 07, 2021, 02:32:56 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline Psi

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Re: Knife Sharpening
« Reply #16 on: August 07, 2021, 02:37:35 am »
I had one of these ones growing up. It was old and a bit rusty but still sharpened knives really really well.
It just kept going and going. Lasted over 25 years and I think dad still has it.

You'd pull the knife through, then rotate the wheel a bit with your thumb, then pull the knife through, repeat 5-30 times.

Obviously a professional knife block and sharpening kit will get you a better edge, but for the price and convenience this one was amazing and lasted forever.

« Last Edit: August 07, 2021, 02:40:49 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline Microdoser

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Re: Knife Sharpening
« Reply #17 on: August 07, 2021, 10:38:24 am »
This is the one I 3D printed (just the black bits) There is also some aluminium tube, some super magnets, a few bolts, and cheap AliExpress sharpening stones (320,800,2000,3000,5000,6000,8000,10000 and leather ones with polishing compound)

Super easy to use, just get the printed angle guide for the angle you want (currently it is set to 20 degrees) then go through the stones, any time you feel a burr on the underneath turn the knife over. If you've turned it over twice, change the stone for a higher grade. I double-check with my bench microscope to make sure I have at least removed any nicks or chips from the edge, also to see when I have removed all the sharpening scratches (when using the 10000 stone).

 

Offline dunkemhigh

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Re: Knife Sharpening
« Reply #18 on: August 11, 2021, 09:59:38 pm »
Quote
So eventually I succumbed and got an AnySharp Plus.

Not long after posting that I noticed Amazon had the Anysharp (standard) on sale for roughly the same price as a set of replacement blades. Hard to resist, so I didn't.

So, this one is in the office for non-kitchen tool stuff. As it happens, today I bought something that came with a plastic security seal label across the tab. No problem: my trusty scalpel-style knife will deal with that, but in fact it didn't. Blade looks OK but it's blunt, so with nothing to lose I wiped it through the Anysharp a couple of a times, not expecting much (it's a scalpel  blade, after all). To my great surprise it put a decent edge on, which went through the label like, er, a hot knife through butter. But less messy.

Thoroughly impressed.
 

Offline AntiProtonBoy

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Re: Knife Sharpening
« Reply #19 on: August 12, 2021, 01:32:13 am »
I had one of these ones growing up. It was old and a bit rusty but still sharpened knives really really well.
It just kept going and going. Lasted over 25 years and I think dad still has it.

You'd pull the knife through, then rotate the wheel a bit with your thumb, then pull the knife through, repeat 5-30 times.

Obviously a professional knife block and sharpening kit will get you a better edge, but for the price and convenience this one was amazing and lasted forever.
Forgot about these! Use to have them in Europe.
 

Online bob91343

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Re: Knife Sharpening
« Reply #20 on: August 12, 2021, 01:43:56 am »
On a related subject, has anyone found an inexpensive but successful way to sharpen razor blades?
 

Offline SeanB

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Re: Knife Sharpening
« Reply #21 on: August 12, 2021, 08:30:22 am »
On a related subject, has anyone found an inexpensive but successful way to sharpen razor blades?

Leather strop works well, you simply push the blade up the taut strop, and it burnishes the edge sharp again. Just has to be a strip cut to the width of the blade in the holder, unless you are using a razor with removeable blades, or a cutthroat razor, which then wants a wide strop.  Barber shop suppliers, or find a local saddler and get a genuine leather belt that is not embossed, and use that.
 

Offline David Hess

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Re: Knife Sharpening
« Reply #22 on: August 12, 2021, 04:20:00 pm »
On a related subject, has anyone found an inexpensive but successful way to sharpen razor blades?

Look into how they used to sharpen scalpels.  I had some luck using my finest white sharpening stone.  A leather strop like SeanB suggests is what I would try first.
 

Online bob91343

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Re: Knife Sharpening
« Reply #23 on: August 12, 2021, 09:31:02 pm »
Most of the methods of sharpening razors involve hardware that costs more than new blades.  I may have an old leather belt I can try.
 

Online duckduck

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Re: Knife Sharpening
« Reply #24 on: August 13, 2021, 07:24:46 am »
I used to do all of the Norton water stones until I saw a YouTube video.

Stuck a disk of 3/4" plywood on my bench grinder. I smoothed it out with sandpaper. Before sharpening I hit it with a bar of white polish. This will sharpen a dulled-sharp blade to shaving sharp in about 60 seconds.

EDIT:

Sorry, I wasn't very clear. White polishing compound is made with fine aluminum oxide powder and some kind of (grease/wax/whatever) base. It is available in bar or paste form. I have attached an example of some I found on a large online shopping site.
« Last Edit: August 27, 2021, 07:03:04 pm by duckduck »
 


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