It is currently Sat Sep 20, 2014 3:56 am



Welcome
Welcome to chefknivestogo

You are currently viewing our boards as a guest, which gives you limited access to view most discussions and access our other features. By joining our free community, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content, and access many other special features. In addition, registered members also see less advertisements. Registration is fast, simple, and absolutely free, so please, join our community today!





 Page 2 of 3 [ 23 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post subject: Re: How sharp knife do I need
PostPosted: Tue Oct 01, 2013 5:31 am 

Joined: Wed Apr 25, 2012 10:29 am
Posts: 625
Location: Philippines
cliff stamp isn't very accepted by people in most kitchen knife forums. just saying.


Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Tue Oct 01, 2013 10:46 am 
Forum Moderator
User avatar

Joined: Mon Apr 23, 2012 4:45 am
Posts: 1398
"cliff stamp isn't very accepted by people in most kitchen knife forums. just saying."

+1 His views lack clarity and although sounding 'scientific' show a consistent lack of critical thinking, often coming to wrong conclusions from poorly formulated data collection strategies. He has also compared VG-10 favorably against M390 steel for instance. Point made.

It is true that precise geometry - a well formed edge - considerably affects edge performance, but the level of finish is also quite important. It is for this reason that I urge people to expend considerable energy learning to form a precise edge at 1k rather than going on to finer grits prematurely. Of course BOTH a precise edge with refinement is the best of both worlds. How fine is determined by the intended task.

IMO one of the nicer videos demonstrating obtaining an extremely high level of performance from a 1k edge is Adam's video of sharpening on a 1k Nubatama speckled Ume. One could learn a great deal from watching this video over and over. He demonstrates easily shaving arm hair and slice cutting paper with ease. Of course a good 1k stone helps too :)



---
Ken



_________________
My Facebook Page
Ken'sCorner
Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Tue Oct 01, 2013 3:47 pm 

Joined: Thu Nov 29, 2012 11:38 pm
Posts: 23
I don't see why what the forums think of him matters to the present point, which is just that an edge that shaves can be obtained off of very coarse grits. Unless you're suggesting his video was faked. Doesn't strike me as likely, but who knows. Regardless, I can shave hair off the low grits I mentioned, and I'm just a mediocre sharpener.

Didn't mean to spark any controversy, or suggest that the level of edge refinement is unimportant, just that OP's edges should shave off a 1k waterstone since that same test can be achieved at much coarser grits with a bit of care. Agreed, Adam's excellent video sets a nice benchmark. And I agree, Ken, that once you've got your hair-popping geometry set you should refine your edge for the best of both worlds!


Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Tue Oct 01, 2013 4:21 pm 
Forum Moderator
User avatar

Joined: Thu Apr 19, 2012 8:34 pm
Posts: 1522
Okay, we're going to clear this up once and for all.

If you make an edge on a kitchen knife with anything less than 800 - 1000 grit, you are going to create all kinds of drag on your product. Yes, I've shaved hair with the latte 400 on a video, no problem with finessing the edge once you've created it. All you have to do is reduce pressure and cleanly deburr after the edge has been met... do this cleanly enough, and presto! Shaves hair! Now, I dare you to bring that coarse scratchy bevel against something more polished and tell me cuts the same. It won't. Shaving hair and cutting ingredients are 2 completely different things. Once the skin of the product is pierced you will have the scratches of the bevel grabbing your product.

Coarse edges grab things and fine polished edge cut smooth like silk. There's a middle ground, and that's anywhere from 1k to 6 - 8k. That's where we tend to stay for kitchen knives, anything sharper begins to reduce edge life. Anything more coarse and cutting action is severely reduced due to drag. Shaving hair only means that you don't need to go back to your coarse stones.

I know some of us have had issues with Cliff, but let's leave that for the birds, no more of that on our forum guys, thanks. :D



_________________
Shaun Fernandez

With great sharpness comes great responsibility.
Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Tue Oct 01, 2013 7:59 pm 

Joined: Tue Mar 05, 2013 1:47 pm
Posts: 74
Location: Oslo Norway
Thanks for all the answers. I have now got a lot of good advices. The autumn has arrived in Norway. Only 32 deg Farhenheit today and dark after seven. I have long,dark winter to practice.



_________________
I am from Norway so therefore bad english!!!
Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Wed Oct 02, 2013 9:54 am 

Joined: Tue Mar 05, 2013 1:47 pm
Posts: 74
Location: Oslo Norway
Knife Fanatic wrote:Okay, we're going to clear this up once and for all.

If you make an edge on a kitchen knife with anything less than 800 - 1000 grit, you are going to create all kinds of drag on your product. Yes, I've shaved hair with the latte 400 on a video, no problem with finessing the edge once you've created it. All you have to do is reduce pressure and cleanly deburr after the edge has been met... do this cleanly enough, and presto! Shaves hair! Now, I dare you to bring that coarse scratchy bevel against something more polished and tell me cuts the same. It won't. Shaving hair and cutting ingredients are 2 completely different things. Once the skin of the product is pierced you will have the scratches of the bevel grabbing your product.

Coarse edges grab things and fine polished edge cut smooth like silk. There's a middle ground, and that's anywhere from 1k to 6 - 8k. That's where we tend to stay for kitchen knives, anything sharper begins to reduce edge life. Anything more coarse and cutting action is severely reduced due to drag. Shaving hair only means that you don't need to go back to your coarse stones.

I know some of us have had issues with Cliff, but let's leave that for the birds, no more of that on our forum guys, thanks. :D


Hello Knife Fanatic:)

Can I use normal pressure when I start grinding on my knife (get a burr on one side, flips around and get a burr on the other side) and reduce the pressure after that?



_________________
I am from Norway so therefore bad english!!!
Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Wed Oct 02, 2013 1:22 pm 
User avatar

Joined: Mon Aug 12, 2013 9:35 pm
Posts: 30
Location: Boston, MA
If we're speaking strictly for the kitchen, a little tooth is a good thing to have in my opinion. Personally, I find a well finished edge between #3 to #4k to be ideal for everyday kitchen use...for your workhorse. Anything above that is generally superfluous (not to say that I don't like playing in the higher grit range or that it can't be useful).
Unless you're sharpening a razor, I'm not quite sure why shaving hair is so highly regarded. It could be my pragmatism, but I just don't consider it as a valid criteria for the kitchen environment...very different requirements.


Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Wed Oct 02, 2013 4:09 pm 
Forum Moderator
User avatar

Joined: Thu Apr 19, 2012 8:34 pm
Posts: 1522
Yes sir, Correct-o. When sharpening, a general rule of thumb is to start with more pressure and gradually reduce as you get further along.

On coarse stones you can start with as much pressure as you want. But, be wary, if you are using an insane amount of pressure you need to be careful. Once a bevel has been ground all the way and you get a burr, you need to either reduce pressure or flip sides. The reason being: The edge actually becomes kind of brittle (especially at lower angles like when thinning) and continuing to apply lots of pressure can cause the edge to get damaged or at the least create some overgrind. So, if you are going to use LOTS of pressure, only do this when you know LOTS of steel needs to be removed. Keep checking your edge while sharpening to see when you should start easing up. The key is to keep the integrity of the steel that is going to be your edge.

Once a burr has been reached you need to reduce pressure and do single strokes, edge-leading I find works better at getting rid of a burr while ensuring you edge is good. Make sure not to change the angle. Biggest thing I can't stress enough. Doesn't matter what angle you are using (as long as it's 20 degrees or under) just make sure you hold that angle. Holding your angle tight while on a coarse stone prevents wasted strokes, increases the speed at which the bevel is cut, and makes a much cleaner looking bevel. Naturally some slight convexing will occur, but this is natural and okay as long as it's kept to a minimum. Try not to wobble your hand, that's what tends to kill an edge.

Shaving hair really depends on 2 things: How clean the edge is of burr and is the edge-of-the-edge rolled? A lot of the time when sharpening 50/50 we will create bevels that are not perfect on each side. Let's say you make a 60/40 edge while grinding on your coarse stone. After you reach the edge you reduce pressure and then begin to sharpen 50/50 again. Sure, for the 60% side this is fine, as the angle is simply increased and the edge is met again within a couple of strokes, but the 40% ground side is not getting hit. So, even if you reduce pressure you will keep pushing the edge over to one side, maybe getting lucky and occasionally hitting it on the other side, causing it to roll over. While it still may seem pretty sharp, it's not going to pop hairs, and actually may have a tiny amount of burr since you keep hitting one side and not the other. This is also the reason why high-tungsten steels (AS) seem to get so spooky sharp so fast: The tungsten really reduces the steel's ability to roll (wear resistance aside). Thinner edges tend to shave better as well.

(edit: Read my next post to clarify that I did not mean edge edge geometry, it was supposed to be angle, sorry for the confusion)



_________________
Shaun Fernandez

With great sharpness comes great responsibility.
Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Wed Oct 02, 2013 9:30 pm 

Joined: Thu Nov 29, 2012 11:38 pm
Posts: 23
Shaun, this is super interesting... A rolled edge is something I've never completely understood (I've rolled my fair share, just couldn't visualize what was happening). Let me see if I'm following:

"A lot of the time when sharpening 50/50 we will create bevels that are not perfect on each side. Let's say you make a 60/40 edge while grinding on your coarse stone."

Do you mean where the 60% side is the result of a lower angle and the 40% side is at a higher angle? Or because you were at the same angle on both sides, but ground more on the 60% side? (Or does it matter which?)

I think you mean the second because I take going back to 50/50 to mean going to alternating sides with each stroke. What I think I don't quite get is why when you do this you don't hit the edge on the 40% side. You mention something about this changing the angle, but I don't get why.

Can you clarify this for my foggy brain? Geometry was never my strong suit ;)


Offline
 Profile  
 
 Post subject: Re: How sharp knife do I need
PostPosted: Thu Oct 03, 2013 1:35 pm 

Joined: Tue Mar 05, 2013 1:47 pm
Posts: 74
Location: Oslo Norway
iancevans wrote:Shaun, this is super interesting... A rolled edge is something I've never completely understood (I've rolled my fair share, just couldn't visualize what was happening). Let me see if I'm following:

"A lot of the time when sharpening 50/50 we will create bevels that are not perfect on each side. Let's say you make a 60/40 edge while grinding on your coarse stone."

Do you mean where the 60% side is the result of a lower angle and the 40% side is at a higher angle? Or because you were at the same angle on both sides, but ground more on the 60% side? (Or does it matter which?)

I think you mean the second because I take going back to 50/50 to mean going to alternating sides with each stroke. What I think I don't quite get is why when you do this you don't hit the edge on the 40% side. You mention something about this changing the angle, but I don't get why.

Can you clarify this for my foggy brain? Geometry was never my strong suit ;)


I have the exact same question. English is not my first language....



_________________
I am from Norway so therefore bad english!!!
Offline
 Profile  
 
Display posts from previous:  Sort by  
 Page 2 of 3 [ 23 posts ]  Go to page Previous  1, 2, 3  Next


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  


suspicion-preferred