Chef's Choice vs. Prof. Knife Sharpening?

[lindag]

19 minutes ago, btbyrd said:

Sorry for the late response... I'd somehow overlooked @JoNorvelleWalker's question above, but Paul's answer above is pretty much exactly what I was going to say. Thinning is not something that many people do to their knives, but most people don't really sharpen them either. If you sharpen on a semi-regular basis, the blade will eventually lose enough height so that it will no longer cut well even when the edge is sharp. The Chef's Choice really only addresses the edge bevel and maybe what's immediately above it, so it won't be able to grind off those thick "shoulders" and restore cutting performance. Thinning knives requires you to use an angle that's more acute than your sharpening angle so that you're actually grinding down the sides of the knife face, and that's not something you can do with most sharpening systems. They're more for maintaining the edge than for maintaining the whole blade. There's nothing wrong with that per se... I still break out my Edge Pro every once in a blue moon to get a super consistent edge on one of my knives. But you can't use it for thinning because it only really cuts along the main edge bevel.

 

Thinning might sound fussy or like something normal people will never need to do, and that's largely true. But if you're using knives with harder steel, their failure mode tends to be chipping along the edge rather than rolling like softer European style knives. Removing chips requires removing a lot of metal compared to normal sharpening, leading to the knife being significantly thicker behind the edge than it was before. So if you do any chip removal at home you'll want to be using a water stone (which does a better job than a system at removing chips) and you'll want to thin the sides of the knife after the chip removal is complete. 

The knives (like my Kramer) that have a 9-12 degree bevel, can they effectively be sharpened in the Edge Pro? (the one with the Asian angle stones.)

[rotuts]

@lindag 

 

I sharpen all my knives w an EdgePro

 

even my Watanabe's

 

email them and ask them specifically what 

 

angle they recommend  for the Kramer  etc.

 

they were familiar w the Watanabe's when I got my first one

 

and gave me excellent advice.

 

do you have an EdgePro ?

[AlaMoi]

the "need" to thin a blade comes from the depicted:

no electric or jig "sharpening" doohickies "thin" the blade.  to thin a blade, long, arduous work on stones, or quicker work on belt type grinders is required - and it's not a good starting task for the inexperienced.

 

electric powered sharpeners tend to remove a lot more metal than hand sharpening, and hence can cause the need to "thin the blade"  - much like 20-30 times sooner - than hand sharpening.

 

for those interested in acquiring the basics of edges and sharpening, look for Chad Ward's "Knife Maintenance and Sharpening"

available here:

https://forums.egullet.org/topic/26036-knife-maintenance-and-sharpening/

[JoNorvelleWalker]

9 hours ago, rotuts said:

@JoNorvelleWalker

 

looking forward to your results

 

what is the platform that the knife is on

 

when you examine it ?

 

a pic or two ?

 

why not try masking tape , the kind the painter use

 

that's easy to peel off ?

 

found a few pics via google :

 

https://prosharpeningsupply.com/blogs/knife-tool-sharpening/knife-sharpening-under-the-microscope

 

https://www.youtube.com/watch?v=FAb0DdF7rrc

 

 

can  not vouch for quality etc

 

Here is a picture of the setup:

 

 

The microscope table is 4.5 inches wide, and only my smallest knife will sit on it without additional support.  I looked at several knives handheld but I don't really know how to see a good edge from bad.  They all look similar.  I'm guessing there probably is a better angle for viewing than just flat.

 

Ideas welcome.

 

[rotuts]

what is the magniication

 

of the unit ?

 

''   1300  ''  is stated on amazon

 

I doubt this can get you 1300 X

[JoNorvelleWalker]

40 minutes ago, rotuts said:

what is the magniication

 

of the unit ?

 

''   1300  ''  is stated on amazon

 

I doubt this can get you 1300 X

 

Ask me again after I've played with it a bit.

 

[JoNorvelleWalker]

7 hours ago, btbyrd said:

Sorry for the late response... I'd somehow overlooked @JoNorvelleWalker's question above, but Paul's answer above is pretty much exactly what I was going to say. Thinning is not something that many people do to their knives, but most people don't really sharpen them either. If you sharpen on a semi-regular basis, the blade will eventually lose enough height so that it will no longer cut well even when the edge is sharp. The Chef's Choice really only addresses the edge bevel and maybe what's immediately above it, so it won't be able to grind off those thick "shoulders" and restore cutting performance. Thinning knives requires you to use an angle that's more acute than your sharpening angle so that you're actually grinding down the sides of the knife face, and that's not something you can do with most sharpening systems. They're more for maintaining the edge than for maintaining the whole blade. There's nothing wrong with that per se... I still break out my Edge Pro every once in a blue moon to get a super consistent edge on one of my knives. But you can't use it for thinning because it only really cuts along the main edge bevel.

 

Thinning might sound fussy or like something normal people will never need to do, and that's largely true. But if you're using knives with harder steel, their failure mode tends to be chipping along the edge rather than rolling like softer European style knives. Removing chips requires removing a lot of metal compared to normal sharpening, leading to the knife being significantly thicker behind the edge than it was before. So if you do any chip removal at home you'll want to be using a water stone (which does a better job than a system at removing chips) and you'll want to thin the sides of the knife after the chip removal is complete. 

 

I watched the video again.  I may be confused how far up from the edge the thinning process begins and ends.  However the blade geometry diagram looks a lot like what is shown in Chef's Choice marketing material.

 

To get an idea what thinning might accomplish I measured my new chef knife.

 

 

Shown here, second from left.

 

Measured midway left to right, and midway from spine to edge, the blade thickness is 1.355 mm.  Measured as close as I could get to the edge, the blade thickness is 0.926 mm.  Would thinning after repeated sharpening make a noticeable difference?

 

[blue_dolphin]

17 minutes ago, JoNorvelleWalker said:

 

Ask me again after I've played with it a bit.

 

Please, please be careful.  I evaluated knife edges in the lab with the knives immobilized in a holder at the correct focal distance from the stereo microscope eyepieces and a light source easy to rotate for forward or backlight illumination without any body parts coming anywhere near the blade. 
Thinking of you doing this freehand with multiple moving parts makes me very nervous!

[JoNorvelleWalker]

2 minutes ago, blue_dolphin said:

Please, please be careful.  I evaluated knife edges in the lab with the knives immobilized in a holder at the correct focal distance from the stereo microscope eyepieces and a light source easy to rotate for forward or backlight illumination without any body parts coming anywhere near the blade. 
Thinking of you doing this freehand with multiple moving parts makes me very nervous!

 

Me too.

 

[btbyrd]

If you're trying to find the right angle at which to sharpen, you can figure it out by coloring in the blade with Sharpie permanent marker. As you sharpen, the part of the blade in contact with the stone (or whatever) will be ground away and the Sharpie will disappear. This will let you easily see what part of the blade you're actually sharpening or thinning and you can adjust your angle accordingly.

 

A PRO TIP: To remove excess Sharpie you can use a dry erase marker. I forget where I learned this trick, but dry erase markers contain a unipolar solvent that will make Sharpie wipe right off. 

 

What thinning looks like depends on the type of knife that you have, but it eventually involves removing steel quite high up on the blade. You can get an idea of what that involves with this video from Jon at JKI. He uses the "Sharpie trick" to show you how to feel for the right angle while thinning. This knife obviously has a different grind than most Western kitchen knives, but the principles involved are the same.

 

 

Here is another demonstration using a knife with a more traditionally Western style grind. It has some small chips that get removed at a high angle. Once the chips are removed, the knife is thinned behind the edge for a centimeter or two. You can see how much of the blade behind the edge has been ground back at around six and a half minutes into the video. Finally, after the chips are gone and the knife has been thinned, the cutting edge is sharpened and polished again. This is one of the videos I found most helpful when learning how to repair similar smally chips on my Takamura knife.

 

 

And I don't know if this link will embed properly, but it's a link to a *heavily* chipped knife that was repaired and thinned by District Cutlery. It's a knife with Grantons or hollows ground into the blade, so you can get an idea of how much steel has been removed where by looking at how the divots were ground away.

 

https://www.instagram.com/p/CgcTW6iOmBo/

 

Those were some biggish chips for sure, but even small chips are a pain in the neck to remove with pull-through sharpeners or rigs like the Edge Pro.

 

If you want to get a preliminary idea of how much thinning a Chef's Choice actually does, you can color in the bottom half of the blade with Sharpie and run it through and see what part of the blade has been ground down. I doubt it will be much compared to what's involved with proper thinning (or even chip repair). These units might remove a lot of metal, but it's mostly from right around the edge itself. 

[JoNorvelleWalker]

@btbyrd, the instagram link would not display for me.

 

Back a couple years ago I measured just how much steel the 1520 Chef's Choice removed from my 9 inch New West chef knife:  0.023 g.  Next time I sharpen I'll try to remember to do the Sharpie test, thanks.

 

https://forums.egullet.org/topic/160092-knife-sharpening/?do=findComment&comment=2263659

 

 

 

[weinoo]

@btbyrd - Does District Cutlery do mail-order sharpening or repairing of badly chipped knives?

 

And is the District Cutlery you refer to this one?  https://www.districtcutlery.com/

[btbyrd]

3 hours ago, weinoo said:

@btbyrd - Does District Cutlery do mail-order sharpening or repairing of badly chipped knives?

 

And is the District Cutlery you refer to this one?  https://www.districtcutlery.com/

Yes and yes. They do great work with a fast turnaround. I had them thin a couple troublesome knives and sharpen a mirror polished one that I don’t like to sharpen myself.

 

Since you’re in NYC, you can also drop your knife off at Korin and have them take care of it. Vincent is their head sharpener, and you can see some of his handiwork on Instagram at vincentsavesknives.

Edited August 29, 2022 by btbyrd (log)

[weinoo]

40 minutes ago, btbyrd said:

Since you’re in NYC, you can also drop your knife off at Korin and have them take care of it. Vincent is their head sharpener, and you can see some of his handiwork on Instagram at vincentsavesknives.

 

I've used Korin for sharpening before (and purchased knives here, as well as a donabe!), but they were definitely out of sync and not sharpening for a while (and currently Knife sharpening is temporarily paused and will resume September 6th).  Good to see them back at it. It's a great store, but if one has a knife fetish... (ahem) be careful.

 

 

 

 

 

 

[JoNorvelleWalker]

6 hours ago, rotuts said:

still wondering about magnification :

 

' X ' when mentioning magnification is ' times '

 

a 10 X magnifies 10 times the original image

 

' the magnification was a little less than 1. '

 

1 x would be no magnification at all.

 

looking at your picture  of the set up

 

Id guess 10 X ?

 

In my picture the knife image is being displayed on the microscope's 10 inch screen.  If I connected the output to my 27 inch computer monitor the image would appear larger, but the resolution wouldn't change.  I would not call that an increase in magnification.  The ridiculous USB microscope magnification numbers rely on the "magnification" of the display device.  If I had a 100 inch television* I could make the knife edge frighteningly immense but I would argue that is not an increase in magnification.

 

*I do not have a television.

 

[JoNorvelleWalker]

The thing I like least about the TOMLOV DM202 is that the stand is so small, 4.5 inches.  With the 10 inch monitor the setup is top heavy and feels like it might tip over.  Worse, as I mentioned, only my little Wusthof 3.5 inch Cordon Bleu will sit on the table unsupported.

 

TOMLOM offers a similar microscope DM402 with a much larger stand and what they say is a higher resolution camera.  But for that price one could buy a knife.

 

Do I keep the DM202 and live with its limitations or do I return it to amazon while I can and get the more useful DM402?  Or do I forget the whole thing and continue to believe Chef's Choice knows best?

 

[Anna N]

21 minutes ago, JoNorvelleWalker said:

Or do I forget the whole thing and continue to believe Chef's Choice knows best?

Yes. This way we are not likely to read about your amputation(s).  We would much rather read about some of the amazing meals that you make. At least I would. 

[rotuts]

@JoNorvelleWalker 

 

keep what you have , and work w it form time to time

 

 

[palo]

I'm a firm believer in always buying the best available, assuming there are objective reasons for "it" being better, so my vote is for the 402

 

p