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View Full Version : A few sharpening tips from a pro



Peco
03-25-2012, 01:35 PM
Man, does it ever end?

http://youtu.be/JFhUXgYS0Os

QUOTE:
The problem of maintaining a constant angle as one approaches the tip of a curved knife is something that vexes many knife sharpeners. I try to demonstrate the correct way to follow a curved blade by using a 'Mock Blade' ground to a 45 degree angle on one side and extra extra thick. On this visual aid, I've marked the blade with marks perpendicular to the edge along both the straight portion and the curved part of the blade as a further visualization to help 'get' how one does this task.

I demonstrate the simplified approach - put the abrasive surface at the angle you wish to sharpen and hold the knife in a horizontal plane. Then I demonstrate if the abrasive surface is horizontal how you do the SAME motion, but in this instance it looks like you are lifting the knife up. I feel that maintaining the knife in a horizontal plane and rotating it is a simpler motion to perform and results in greater accuracy.

There are many people who describe various contortions to achieve this simple highly repetitive motion, referring to 'lifting the knife' , 'twisting the knife' and various confused descriptions.

I hope this clarifies the basic geometry behind the mechanics of maintaining a consistent angle around the curve as one approaches the tip.

Hope you guys like my first knife design, LOL It's a style that will be a big hit on KKF where they might actually think that I made a knife.

---
Ken


......................

Does this medical condition have a name?

Andrew H
03-25-2012, 01:41 PM
'Perpendicular to the tangent of your edge.'

maxim
03-25-2012, 01:58 PM
I like how he made a model not of a knife but straight edge. It dose not curve or anything haha.... I will like to see him do the same with a knife that narrows down to the tip.
Then angle actually changeges, when you come to tip aria and make your tip super weak, it just shows how pro that guy is :rofl2:

Peco
03-25-2012, 02:10 PM
In a few weeks you can buy this device that will help you maintain your angle while sharpening. You can buy it .... well you know where :idea2:

Dave Martell
03-25-2012, 02:55 PM
Stupid can't be fixed.

Andrew H
03-25-2012, 02:55 PM
In a few weeks you can buy this device that will help you maintain your angle while sharpening. You can buy it .... well you know where :idea2:

Where is the piece of plastic that locks your wrist and fingers in place?

Peco
03-25-2012, 03:07 PM
Where is the piece of plastic that locks your wrist and fingers in place?

Just keep them steady and twist your body from side to side. As a bonus you will get a sixpack (maybe a sore back) - what more can you ask for :D This might be the next big thing: Ken's sharp-n-abs ... keeps your knifes sharp and your body fit. :stinker:

Dave Martell
03-25-2012, 03:20 PM
Just keep them steady and twist your body from side to side. As a bonus you will get a sixpack (maybe a sore back) - what more can you ask for :D This might be the next big thing: Ken's sharp-n-abs ... keeps your knifes sharp and your body fit. :stinker:


Interesting that you picked up on this. :thumbsup:

I train about 4-6 professional knife sharpeners a year and most all of them come to me with pre-conceived notions that they've garnered from internet misinformation or their own lack of hands on experience. One of the biggest hurdles for an inexperienced belt sharpener to overcome is to understand that this technique (shown in the video) only works on some knives. It is a simple way for an inexperienced sharpener to understand the basics and provide decent results so it's understandable how and why they use this. The thing is that upon handling a vast array of knives (at hundreds at a time) the reality sets in that this method lacks for several reasons. The very first thing that hits a pro sharpener is fatigue from twisting at the waist, then there's the issue of the physical limitation of not being able to fully twist one's body enough to grind the entire edge of many knives (ie - butcher knives like the scimitar or bull nose styles), and then there's the distal tapered knives (like Japanese knives or higher end customs) that show an over grind at the tip from using this method.

So my point is that this seems like the simple explanation but in reality it's extremely impractical and it's also somewhat incorrect in most cases. It's a shame that this type of mis-information still gets touted as fact but that's YouTube for ya.

Dave Martell
03-25-2012, 03:32 PM
This is the ONLY correct professional style knife sharpening technique that I've come across on YouTube. The presenter doesn't show perfect technique but he does show how to do the motions.

If this technique is used you can sharpen any and all knife types regardless of their profiles or grinds using a belt and get perfect results every time.

See 4:34 & 5:52 marks


http://www.youtube.com/watch?v=fYURcwkKGPs

Peco
03-25-2012, 03:34 PM
I agree Dave. The internet contains good info BUT a lot more incorrect stuff for sure. One has to be selective and not trust everything written in cyberspace. Best way to get knowledge is hands on with a specialist - nothing beats that.

Don Nguyen
03-25-2012, 05:56 PM
That's a pretty cool little stone wheel. I wonder how much something like that costs?

dragonlord
03-25-2012, 06:16 PM
249 (http://www.google.co.uk/products/catalog?q=tormek+sharpening&oe=UTF-8&hl=en-gb&client=safari&um=1&ie=UTF-8&tbm=shop&cid=7865105687135577510&sa=X&ei=9JhvT9TnBcTi8APor_i_DQ&ved=0CEIQ8wIwBA)

Dave Martell
03-25-2012, 06:38 PM
That's a pretty cool little stone wheel. I wonder how much something like that costs?


It's not cheap and it can't do low angles (like we use) unless you free hand on it.

Overall it's a well constructed machine but it's really only OK for the once in awhile edge. I could write a book on it's flaws for the professional sharpener's use.

Don Nguyen
03-25-2012, 07:03 PM
Jeebus that's expensive.

If I were to have something like that (for much less than that cost) it'd probably just be an alternative to my DMT or sander.

steeley
03-25-2012, 07:05 PM
I learned a long time ago that there is a lot of misinformation on the subject of sharpening .
if you listen to every guy that claims they know what there talking about because they have a burr king or sell things or have a lot stones and like to type
there the man with the answer and tell you other's are wrong need there diaper changed.
it is about learning to be a better sharpener and learn from the right people and since Dave is right at the top of the game and has the #1 forum for kitchen knife talk people like to throw rocks and throw little fits .

Eamon Burke
03-25-2012, 09:52 PM
That Tormek looks like a really cool, considerate device. But it would take a mastermind to figure out how to make money with one.

I can see why it'd be useful for finishing edged tools in a factory setting. Or a dedicated sharpener in a meat packing plant(if meat packers gave 2 shytes about their employees).

dragonlord
03-26-2012, 01:46 AM
How about $2 a knife or 5 for $8 in a supermarket?

dragonlord
03-26-2012, 01:51 AM
ESP. If you also do knife use lessons for $5 for basic cutting techniques (how to hold the knife, push, pull, chop, and rocking cuts)

TB_London
03-26-2012, 05:35 AM
For knives the Tormek are easy to put overgrinds into the edge, I used to use one for woodworking tools and the jigs allow for repeatable edges on a lot of tools. Flexible knives also go crazy unless you're really careful. With a few mods you can jig them to go to lower angles and I've used one to thin some cheaper knives. If I could I'd get a belt grinder but until i move out of my tiny flat i dont have the choice due to space, noise and dust.

That video is a bit of a strange one, unless the geometry of a knife is equivalent to a plank. The asymmetric thread over there got pretty cringe inducing as well

dav
03-26-2012, 06:37 AM
I'm considering purchasing a home grinder but have the "luxury" of being able to use a very expensive/professional horizontal grinder, it uses oil rather than water and rpm is slow so no danger of over heating is this the best option (not wanting to hijack the thread just a very opportune moment for another newbie question), its not mine but I can use whenever I wish?

ecchef
03-26-2012, 07:11 AM
That guy sounds exactly like Dave Emory!

bieniek
03-26-2012, 02:09 PM
For knives the Tormek are easy to put overgrinds into the edge

I have one and I didnt noticed. It actually leaves quite good straight edge and I repeated it on some knives few times and still no holes. There is some limitations to the machine but overgrinds are users fault, not machines